Check your hard disk for errors

Check your hard disk for errors

You can help solve some computer problems and improve the performance of your computer by making sure that your hard disk has no errors.

1.  Open Computer by clicking the Start button Picture of the Start button, and then clicking Computer.

2.   Right-click the hard disk drive that you want to check, and then click Properties.

3.Click the Tools tab, and then, under Error-checking, click Check Now. Administrator permission     required  If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

4.To automatically repair problems with files and folders that the scan detects, select Automatically fix file system errors. Otherwise, the disk check will simply report problems but not fix them.

 5.To perform a thorough disk check, select Scan for and attempt recovery of bad sectors. This scan attempts to find and repair physical errors on the hard disk itself, and it can take much longer to complete.

6. To check for both file errors and physical errors, select both Automatically fix file system errors and Scan for and attempt recovery of bad sectors.

7.Click Start.

8.Depending upon the size of your hard disk, this may take several minutes. For best results, don't use your  computer for any other tasks while it's checking for errors.

Note:

If you select Automatically fix file system errors for a disk that is in use (for example, the partition that contains Windows), you'll be prompted to reschedule the disk check for the next time you restart your computer.

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What is Hardware?

             What is Hardware?

Your PC (Personal Computer) is a system, consisting of many components. Some of those components, like Windows XP, and all your other programs, are software. The stuff you can actually see and touch, and would likely break if you threw it out a fifth-story window, is hardware.

Not everybody has exactly the same hardware. But those of you who have a desktop system, like the example shown in Figure 1, probably have most of the components shown in that same figure. Those of you with notebook computers probably have most of the same components. Only in your case the components are all integrated into a single book-sized portable unit.

The system unit is the actual computer; everything else is called a peripheral device. Your computer's system unit probably has at least one floppy disk drive, and one CD or DVD drive, into which you can insert floppy disks and CDs. There's another disk drive, called the hard disk inside the system unit, as shown in Figure 2. You can't remove that disk, or even see it. But it's there. And everything that's currently "in your computer" is actually stored on that hard disk. (We know this because there is no place else inside the computer where you can store information!).

The floppy drive and CD drive are often referred to as drives with removable media or removable drives for short, because you can remove whatever disk is currently in the drive, and replace it with another. Your computer's hard disk can store as much information as tens of thousands of floppy disks, so don't worry about running out of space on your hard disk any time soon. As a rule, you want to store everything you create or download on your hard disk. Use the floppy disks and CD s to send copies of files through the mail, or to make backup copies of important items.

                         Random Access Memory (RAM)

There's too much "stuff" on your computer's hard disk to use it all at the same time. During the average session sitting at the computer, you'll probably use only a small amount of all that's available. The stuff you're working with at any given moment is stored in random access memory (often abbreviated RAM, and often called simply "memory"). The advantage using RAM to store whatever you're working on at the moment is that RAM is very fast. Much faster than any disk. For you, "fast" translates to less time waiting and more time being productive.

So if RAM is so fast, why not put everything in it? Why have a hard disk at all? The answer to that lies in the fact that RAM is volatile. As soon as the computer is shut off, whether intentionally or by an accidental power outage, every thing in RAM disappears, just as quickly as a light bulb goes out when the plug is pulled. So you don't want to rely on RAM to hold everything. A disk, on the other hand, holds its information whether the power is on or off.
                                                                 
                                          Hard Disk

All of the information that's "in your computer", so to speak, is stored on your computer's hard disk. You never see that actual hard disk because it's sealed inside a special housing and needs to stay that way. Unlike RAM, which is volatile, the hard disk can hold information forever -- with or without electricity. Most modern hard disks have tens of billions of bytes of storage space on them. Which, in English, means that you can create, save, and download files for months or years without using up all the storage space it provides.

In the unlikely event that you do manage to fill up your hard disk, Windows will start showing a little message on the screen that reads "You are running low on disk space" well in advance of any problems.  In fact, if that message appears, it won't until you're down to about 800 MB of free space. And 800 MB of empty space is equal to about 600 blank floppy disks. That's still plenty of room!

       Mouse

Obviously you know how to use your mouse, since you must have used it to get here. But let's take a look at the facts and buzzwords anyway. Your mouse probably has at least two buttons on it. The button on the left is called the primary mouse button, the button on the right is called the secondary mouse button or just the right mouse button. I'll just refer to them as the left and right mouse buttons. Many mice have a small wheel between the two mouse buttons, as illustrated in Figure .

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Internet

                                    What is the Internet?



The Internet is millions of computers throughout the world, all connected by cables. In professional networking diagrams, the Internet is always displayed as a cloud like in Figure 1.1.6. The cloud is a good analogy because just as a cloud is made up of millions of tiny water droplets, the Internet is made up of millions of computers.You connect to the Internet through a device called a modem, and an ISP (Internet Service Provider). Your ISP might be MSN, America Online, Comcast, Juno, or any of several hundred other companies.


 The term online means "connected to the Internet". When your computer is online, you have access to all the stuff on the Internet, as well as all the stuff on your local hard disk. The term offline means "not connected to the Internet", sort of like snipping the wire that runs from your computer to your ISP. When you're offline, you only have access to the stuff that's on your own hard disk. You can't get to things on the Internet when you're offline.

The Internet provides many services, the most popular being e-mail and the World Wide Web (also known as the Web). The program you use to do e-mail is not Windows XP. Rather, it's some other program, known as an e-mail client. Your e-mail client might be America Online, MSN, Outlook Express, or any of a dozen or so other programs.

The program you use to access the Web is called a Web browser, and yours might be Microsoft Internet Explorer, MSN Explorer, America Online, Netscape Navigator, or something else. The page you're reading right now is a Web page, and you're viewing it with your Web browser.

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Hardware (2)

 The idea is to rest your hand comfortably on the mouse, with your index finger touching (but not pressing on) the left mouse button. Then, as you move the mouse, the mouse pointer (the little arrow on the screen) moves in the same direction. When moving the mouse, try to keep the buttons aimed toward the monitor  don't "twist" the mouse as that just makes it all the harder to control the position of the mouse pointer.

If you find yourself reaching too far to get the mouse pointer where you want it to be on the screen, just pick up the mouse, move it to where it's comfortable to hold it, and place it back down on the mousepad or desk. The buzzwords that describe how you use the mouse are as follow

            Point: To point to an item means to move the mouse pointer so that it's touching the item.

           Click: Point to the item, then tap (press and release) the left mouse button.

           Double-click: Point to the item, and tap the left mouse button twice in rapid succession - click-click  as fast as you can.

           Right-click: Point to the item, then tap the mouse button on the right.

    Drag: Point to an item, then hold down the left mouse button as you move the mouse. To drop the item, release the left mouse button.

          Right-drag: Point to an item, then hold down the right mouse button as you move the mouse. To drop the item, release the right mouse button.


                                           
                                         Keyboard

Like the mouse, the keyboard is a means of interacting with your computer. You really only need to use the keyboard when you're typing text. Most of the keys on the keyboard are laid out like the keys on a typewriter. But there are some special keys like Esc (Escape), Ctrl (Control), and Alt (Alternate). There are also some keys across the top of the keyboard labeled F1, F2, F3, and so forth. Those are called the function keys, and the exact role they play depends on which program you happen to be using at the moment.

Most keyboards also have a numeric keypad with the keys laid out like the keys on a typical adding machine. If you're accustomed to using an adding machine, you might want to use the numeric keypad, rather than the numbers across the top of the keyboard, to type numbers. It doesn't really matter which keys you use. The numeric keypad is just there as a convenience to people who are accustomed to adding machines.

Most keyboards also contain a set of navigation keys. You can use the navigation keys to move around around through text on the screen. The navigation keys won't move the mouse pointer. Only the mouse moves the mouse pointer.

On smaller keyboards where space is limited, such as on a notebook computer, the navigation keys and numeric keypad might be one in the same. There will be a Num Lock key on the keypad. When the Num Lock key is "on", the numeric keypad keys type numbers. When the Num Lock key is "off", the navigation keys come into play. The Num Lock key acts as a toggle. Which is to say, when you tap it, it switches to the opposite state. For example, if Num Lock is on, tapping that key turns it off. If Num Lock is off, tapping that key turns Num Lock on.

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Identify and Avoid Phishing Scams

How to Identify and Avoid Phishing Scams

 Phishing is a form of social engineering technique used by hackers to gather sensitive information such as usernames, passwords and credit card details by posing as a trust worty person/organization. Since most online users are unaware of the techniques used in carrying out a phishing attack, they often fall victims and hence, phishing can be very effective.

With the dramatic increase in the number of phishing scams in the recent years, there has also been a steady rise in the number of people being victimized. Lack of awareness among the people is the prime reason behind such attacks. This article will try to create awareness and educate the users about such online scams and frauds.

Phishing scams usually sends an email message to users requesting for their personal information, or redirects them to a website where they are required to enter their personal information. Here are some of the tips that can be used to identify various phishing techniques and stay away from it.

                                             Identifying a Phishing Scam

1. Beware of emails that demand for an urgent response from your side. Some of the examples are:

    You may receive an email which appears to have come from your bank or financial organization stating that   “your bank account is limited due to an unauthorized activity. Please verify your account asap so as to avoid permanent suspension”. In most cases, you are requested to follow a link (URL) that takes you to spoofed webpage (similar to your bank website) and enter your login details over there. In some cases, phishing emails may ask you to make a phone call. There may be a person or an audio response waiting on the other side of the phone to take away your credit cards details, account number, social security number or other valuable data.

2. Phishing emails are generally not personalized. Since they target a large number of online users, they usually use generalized texts like “Dear valued customer”, “Dear Paypal user” etc. to address you. However, some phishing emails can be an exception to this rule.

3. When you click on the links contained in a phishing email, you will most likely be taken to a spoofed webpage with official logos and information that looks exactly same as that of the original webpages of your bank or financial organization. Pay attention to the URL of a website before you enter any of your personal information over there. Even though malicious websites look identical to the legitimate site, it often uses a different domain or variation in the spelling. For example, instead of paypal.com, a phishing website may use different addresses such as:

•  papyal.com

•   paypal.org

• verify-paypal.com

•  xyz.com/paypal/verify-account/

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Identify Safe Websites

Identify Safe Websites on the Internet

Safe Websites

On the whole Internet, there are approximately more than 150 million active websites up and running. As a result, it often becomes a real challenge for the users to identify safe websites that are trustworthy and reputed. Have you ever wondered to know the reputation of a website before placing the order? Need to know whether a given website is child safe? Well, here are some of the ways to identify safe websites on the Web.


1. WOT or Web Of Trust (www.mywot.com):

WOT is a great place to test the reputation of your favorite website. WOT gives real-time ratings for every website based on the feedback that it gets from millions of trustworthy users across the globe and trusted sources, such as phishing and malware blacklists. Each domain name is evaluated based on this data and ratings are applied to them accordingly. A snapshot of WOT ratings for gohacking.com is shown below As shown in the above snapshot, the reputation of each website is shown in terms of 4 components where green means excellent, yellow warns users to be cautious and red indicates potential danger.


Trustworthiness signifies the overall safety of the website. A poor rating may indicate that the site is associated with threats like Internet scams, phishing, identity theft risks and malware. For more information on phishing, you may refer my other post on how to identify and avoid phishing scams.


Vendor reliability tells you whether a given site is safe for carrying out buy and sell transactions with it. An excellent rating indicates superior customer satisfaction while a poor rating indicates possible scam or bad shopping experience.

Privacy indicates about “to what extent the site respects the privacy of it’s users and protects their personal identity and data”.


Child Safety indicates whether the content of a given site is appropriate for children. Site contents like sexual material, nudity and vulgarity will have a poor Child Safety rating.


In most cases, the WOT ratings are found to be highly accurate. To check the reputation of any given website, just visit www.mywot.com type-in the address of your favorite website and click on “Check now”. This tool alone can tell you a lot about the reputation and safety level of a website. However, in addition to this, I am giving you another 3 handy tools to identify safe websites on the Web.


2. McCafee SiteAdvisor:

McCafee SiteAdvisor is a free tool that is available as a browser add-on. It adds safety ratings to your browser and search engine results. You can download it from www.siteadvisor.com.


3. StopBadware:

Using this tool, you can check whether a given site is said to have involved in malware activity in the past. To check this, go to http://www.stopbadware.org/home/reportsearch and enter the URL or domain name of a website and click on “Search Clearinghouse ”. If the search does not return any result, that means the site was never involved in any of the malware activity in the past.


4. Google Pagerank:

Google PageRank is another great tool to check the reputation and popularity of a website. The PageRank tool rates every webpage on a scale of 1 to 10 which indicates Google’s view of importance of the page. If a given website has a PageRank of less than 3, then it is said to be less popular among the other sites on the Internet.


However, PageRank will only tell you how much popular a given website is and has nothing to do with the safety level of a website. So, this tool alone cannot be used to evaluate a website’s safety and other factors.


PageRank feature is available as a part of Google Toolbar. You can install Google Toolbar from http://www.google.com/intl/en_uk/toolbar/ie/index.html.

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Computer History

 What is a computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem.

Conventionally a computer consists of some form of memory for data storage, at least one element that carries out arithmetic and logic operations, and a sequencing and control element that can change the order of operations based on the information that is stored. Peripheral devices allow information to be entered from an external source, and allow the results of operations to be sent out.

A computer's processing unit executes series of instructions that make it read, manipulate and then store data. Conditional instructions change the sequence of instructions as a function of the current state of the machine or its environment.

The first electronic computers were developed in the mid-20th century (1940–1945). Originally, they were the size of a large room, consuming as much power as several hundred modern personal computers (PCs).

Modern computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space. Simple computers are small enough to fit into mobile devices, and mobile computers can be powered by small batteries. Personal computers in their various forms are icons of the Information Age and are what most people think of as "computers". However, the embedded computers found in many devices from mp3 players to fighter aircraft and from toys to industrial robots are the most numerous.

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Parts of the computer

1. Motherboard


The motherboard is the main component inside the case. It is a large rectangular board with integrated circuitry that connects the other parts of the computer including the CPU, the RAM, the disk drives (CD, DVD, hard disk, or any others) as well as any peripherals connected via the ports or the expansion slots.

Components directly attached to the motherboard include:

• The central processing unit (CPU) performs most of the calculations which enable a computer to function, and is sometimes referred to as the "brain" of the computer. It is usually cooled by a heat sink and fan.

• The chip set mediates communication between the CPU and the other components of the system, including main memory.

• RAM (random-access memory) stores resident part of the current running OS (OS core and so on) and all running processes (application parts, using CPU or input/output (I/O) channels or waiting for CPU or I/O channels).

• The BIOS includes boot firmware and power management. The Basic Input Output System tasks are handled by operating system drivers.

• Internal buses connect the CPU to various internal components and to expansion cards for graphics and sound.

•  Current

• The north bridge memory controller, for RAM and PCI Express

• PCI Express, for expansion cards such as graphics and physics processors, and high-end  network interfaces

• PCI, for other expansion cards

• SATA, for disk drives

• ATA

        Obsolete

•  AGP (superseded by PCI Express)

•  VLB VESA Local Bus (superseded by AGP)

•   ISA (expansion card slot format obsolete in PCs, but still used in industrial computers)

            External bus controllers support ports for external peripherals. These ports may be controlled    directly by the south bridge I/O controller or based on expansion cards attached to the motherboard through the PCI bus.

• USB

• FireWire

• SATA

• SCSI

2. Power supply

A power supply unit (PSU) converts alternating current (AC) electric power to low-voltage DC power for the internal components of the computer. Some power supplies have a switch to change between 230 V and 115 V. Other models have automatic sensors that switch input voltage automatically, or are able to accept any voltage between those limits. Power supply units used in computers are nearly always switch mode power supplies (SMPS). The SMPS provides regulated direct current power at the several voltages required by the motherboard and accessories such as disk drives and cooling fans.

3. Removable media devices 

      CD (compact disc) - the most common type of removable media, suitable for music and data.
      CD-ROM Drive - a device used for reading data from a CD.
      CD Writer - a device used for both reading and writing data to and from a CD.
      DVD (digital versatile disc) - a popular type of removable media that is the same dimensions as a  CD  but stores up to 12 times as much information. It is the most common way of transferring digital video, and is  popular for data storage.
       

      DVD-ROM Drive - a device used for reading data from a DVD.
      DVD Writer - a device used for both reading and writing data to and from a DVD.
      DVD-RAM Drive - a device used for rapid writing and reading of data from a special type of                 DVD.Blu-ray Disc - a high-density optical disc format for data and high-definition video. Can store 70 times as  much information as a CD.
        

       BD-ROM Drive - a device used for reading data from a Blu-ray disc.
       BD Writer - a device used for both reading and writing data to and from a Blu-ray disc.
       HD DVD - a discontinued competitor to the Blu-ray format.
       Floppy disk - an outdated storage device consisting of a thin disk of a flexible magnetic storage medium. Used today mainly for loading RAID drivers.Iomega Zip drive - an outdated medium-capacity removable disk storage system, first introduced by Iomega in 1994.
       

      USB flash drive - a flash memory data storage device integrated with a USB interface, typically small, lightweight, removable, and rewritable. Capacities vary, from hundreds of megabytes (in the same ballpark as CDs) to tens of gigabytes (surpassing, at great expense, Blu-ray discs).
     

     Tape drive - a device that reads and writes data on a magnetic tape, used for long term storage and backups.

4. Secondary storage

Hardware that keeps data inside the computer for later use and remains persistent even when the computer has no power.

     Hard disk - for medium-term storage of data.
   Solid-state drive - a device similar to hard disk, but containing no moving parts and stores data in a digital    format.
     
     RAID array controller - a device to manage several internal or external hard disks and optionally some peripherals in order to achieve performance or reliability improvement in what is called a RAID array.

5. Sound card


Enables the computer to output sound to audio devices, as well as accept input from a microphone. Most modern computers have sound cards built-in to the motherboard, though it is common for a user to install a separate sound card as an upgrade. Most sound cards, either built-in or added, have surround sound capabilities.

6. Input and output peripherals


Input and output devices are typically housed externally to the main computer chassis. The following are either standard or very common to many computer systems.

7. Input

•     Text input devices

        Keyboard - a device to input text and characters by depressing buttons (referred to as keys or buttons).

•     Pointing devices

        Mouse - a pointing device that detects two dimensional motion relative to its supporting surface.
        Optical Mouse - uses light to determine mouse motion.
      Trackball - a pointing device consisting of an exposed protruding ball housed in a socket that detects rotation about two axes.
        Touchscreen - senses the user pressing directly on the display

•     Gaming devices

        Joystick - a control device that consists of a handheld stick that pivots around one end, to detect angles in two or three dimensions and reports its angle or direction to the device it is controlling.
        Game pad - a hand held game controller that relies on the digits (especially thumbs) to provide input.
        Game controller - a specific type of controller specialized for certain gaming purposes.Image, Video input devices
        Image scanner - a device that provides input by analyzing images, printed text, handwriting, or an object.
        Web cam - a video camera used to provide visual input that can be easily transferred over the internet.  Audio input devices
        Microphone - an acoustic sensor that provides input by converting sound into electrical signals.









 8. Output


    Printer - a device that produces a permanent human-readable text of graphic document.

•     Speakers - typically a pair of devices (2 channels) which convert electrical signals into audio.

        Headphones - for a single user hearing the audio.

•     Monitor - an electronic visual display with textual and graphical information from the computer.

        CRT - (Cathode Ray Tube) display
        LCD - (Liquid Crystal Display) as of 2010, it is the primary visual display for personal computers.
        LED - (light-emitting diode) display
        OLED - Organic Light-Emitting Diode

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