Wednesday, February 8, 2012

Computer Viruses and Computer Worm

There are two kind of microbe for computer, soft microbe and hard microbe. Soft microbe mean microbe made by human this is a software able to make program damage, but hard microbe is a dirt that can make damage of all your computer parts.

Computer Viruses

A virus is a self-replicating program that spreads by inserting copies of itself into programs or documents that already exist on a computer. The name comes from an analogy with biological viruses. These cannot reproduce by themselves but make use of the functions of infected cells to spread. Similarly, a computer virus makes use of the executable code in legitimate programs to carry out its purposes. A virus may be designed to be destructive to a system or to be a prank. In either case, the virus will rapidly reproduce itself until the system may be overwhelmed. Viruses spread to other systems when infected programs are copied to another machine. Documents with executable code like Word macros can also be vectors of infection. A very common method of spreading viruses is by attachments to email . Today a variant of a virus known as a worm is more often used.


Computer Worms

Viruses and worms are often lumped together in the single category of virus but there is technical distinction. A worm differs from a virus in that it contains all the code it needs to carry out its purposes and does not depend on using other programs. Most recent instances of malware have been worms, spread primarily by email. Worms are designed to replicate rapidly and to use the Internet or other networks to spread with great facility. They may contain code to damage or erase files or may carry other malicious payloads. On a number of occasions, large numbers of computer systems have been brought down by worms. In addition to the damage from whatever payload they carry, the sheer number of worm copies can bring systems to a halt.
A very common method of spreading is by use of any email addresses on an infected computer. The worm searches address books, temporary Internet caches and other possible sources of email addresses. The worm then mails out random infected fake messages. It may use the addresses it finds not only as recipients but also may spoof mail to show them as senders. It may also combine random pieces of addresses into new fake addresses. All the messages will contain an attachment that is infected. None of this activity may be known by the owner of the infected machine and may go on for weeks or months. A single infected machine can send out thousands of worm-carrying messages.

Friday, February 3, 2012

Sticky Keys, Toggle Keys and Mouse Keys

To press shift button five times usually your computer will deactivate of sticky Keys. What the sticky keys, here is the description.

StickyKeys
Sticky Keys is a keyboard feature that enables you to press a modifier key (CTRL, ALT, or SHIFT), or the Windows logo key, and have it remain active until a non-modifier key is pressed. This is useful for people who have difficulty pressing two keys simultaneously.

ToggleKeys
A feature that sets your keyboard to beep when one of the locking keys (CAPS LOCK, NUM LOCK, or SCROLL LOCK) is turned on or off.

FilterKeys
A keyboard feature that instructs your keyboard to ignore brief or repeated keystrokes. You can also adjust the keyboard repeat rate, which is the rate at which a key repeats when you hold it down

MouseKeys
A keyboard feature that enables you to use the numeric keypad to move the mouse pointer and to click, double-click, and drag.

Stop error
A serious error that affects the operating system and that could place data at risk. The operating system generates an obvious message, a screen with the Stop error, rather than continuing on and possibly corrupting data. Stop error is also called a fatal system error.

To turn on StickyKeys
StickyKeys is designed for people who have difficulty holding down two or more keys simultaneously. When a shortcut requires a key combination, such as CTRL+P, StickyKeys will enable you to press a modifier key (CTRL, ALT, or SHIFT), or the Windows logo key ( ), and have it remain active until another key is pressed.

  • Open Accessibility Options.

  • On the Keyboard tab, under StickyKeys, select the Use StickyKeys check box.

To turn off StickyKeys, clear the Use StickyKeys check box.

Guidance:
To open Accessibility Options, click Start, click Control Panel, and then double-click Accessibility Options.
If the Use shortcut check box in the Settings for StickyKeys dialog box is selected, you can turn StickyKeys on or off by pressing the SHIFT key five times.

For more information on changing StickyKeys options, click Related Topics.