Tip & How-To about Computers & Internet

10 reasons why PCs crash-You must know tip 6

6 Viruses

Often the first sign of a virus infection is instability. Some viruses erase the boot sector of a hard drive, making it impossible to start. This is why it is a good idea to create a Windows start-up disk. Go to

* Start-Settings-Control Panel-Add/Remove Programs

Here, look for the Start Up Disk tab. Virus protection requires constant vigilance.

A virus scanner requires a list of virus signatures in order to be able to identify viruses. These signatures are stored in a DAT file. DAT files should be updated weekly from the website of your antivirus software manufacturer.

An excellent antivirus programme is McAfee VirusScan by Network Associates ( www.nai.com). Another is Norton AntiVirus made by Symantec ( www.symantec.com).

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3 Answers

example of computer viruses


virus can be many tyoes as file virus, hidden virus, boot sector virus and other types of virus

Jul 05, 2011 | Computers & Internet

1 Answer

kinds of computer virus


from your question, what are the kinds of computer viruses, here is the detailed explanation:

Computermag-glass_10x10.gif viruses are generally defined as a program inputted into a computer that allows replication of the program installed. As it replicates, the program intentionally infects the computer, typically without even the user knowing about the damage being done. A virus, unlike worms or Trojan horses, needs an aid to transfer them to computers. Viruses usually take a large amount of computer memory, resulting into system crashes. Viruses are categorized to several parts based on its features.
Macro Viruses A macro virus, often scripted into common application programs such as Word or Excel, is spread by infecting documents. Macro viruses are known to be platform-independent since the virus itself are written in language of the application and not the messagebox_info.png operating system. When the application is running, this allows the macro virus to spread amongst the operating systemsmag-glass_10x10.gif. There are thousands of macro viruses that exists, and each are considered major threats. Examples of these viruses are: Melissa.A and Bablas. pc.
Network Viruses Network viruses rapidly spreads through a Local Network Area ( messagebox_info.png LAN), and sometimes throughout the internet. Generally, network viruses multiply through shared resources, i.e., shared drives and folders. When the virus infects a computer, it searches through the network to attack its new potential prey. When the virus finishes infecting that computer, it moves on to the next and the cycle repeats itself. The most dangerous network viruses are Nimda and SQLSlammer.
Logic Bombs The messagebox_info.png logic bomb virus is a piece of code that are inputted into a software system. When a certain and specific condition is met, such as clicking on an internet browser or opening a particular file, the logic bomb virus is set off. Many programmers set the malicious virus off during days such as April Fools Day or Friday the 13th. When the virus is activated, then various activities will take place. For example, files are permanently deleted.
Companion Viruses Companion viruses takes advantage of MS- messagebox_info.png DOS. This virus creates a new file with typically the messagebox_info.png .COM extensions, but sometimes the .EXD extension as well. When a user manually types in a program they desire without adding .EXE or any other specific extention, DOS will make the assumption that the user want the file with the extension that comes first in alphabetical order, and thus running the virus. The companion virus is rare among Windows XP computers as this particular operating system does not use the MS-DOS.
Boot Sector Viruses messagebox_info.png Boot sector viruses generally hide in the boot sector, either in the bootable disk or the messagebox_info.png hard drive. Unlike most viruses, this virus does not harm the files in the hard disk, but harm the hard disk itself. Boot sector viruses are uncommon at this day and age because these viruses are spread rapidly by floppy disks and not on CD-ROMs.
Multipartite Viruses Multipartite viruses are spreaded through infected media and usually hides in the memory. Gradually, the virus moves to the boot sector of the hard drive and infects executable files on the hard drive and later across the computer system

Oct 04, 2010 | Computers & Internet

1 Answer

i cant identify the prolem


It looks like you may have a boot sector virus. A boot sector virus is one that infects the first sector, i.e. the boot sector, of a floppy disk or hard drive. Boot sector viruses can also infect the MBR. All disks and hard drives are divided into small sectors. The first sector is called the boot sector and contains the Master Boot Record (MBR). The MBR contains the information concerning the location of partitions on the drive and reading of the bootable operating system partition.

When disinfecting a boot sector virus, the system should always be booted from a known clean system disk. On a DOS-based PC, a bootable system disk can be created on a clean system running the exact same version of DOS as the infected PC. From a DOS prompt, type:
    SYS C:\ A:\
and press enter. This will copy the system files from the local hard drive (C:\) to the floppy drive (A:\).
If the disk has not been formatted, the use of FORMAT /S will format the disk and transfer the necessary system files. On Windows 3.1x systems, the disk should be created as described above for DOS-based PC's. On Windows 95/98/NT systems, click Start | Settings | Control Panel | Add/Remove Programs and choose the Startup Disk tab. Then click on "Create Disk". Windows 2000 users should insert the Windows 2000 CD-ROM into the CD-ROM drive, click Start | Run and type the name of the drive followed by bootdisk\makeboot a: and then click OK. For example:
    d:\bootdisk\makeboot a:
Follow the screen prompts to finish creating the bootable system disk. In all cases, after the creation of the bootable system disk, the disk should be write protected to avoid infection.

Once the OS loads, run your anti-virus software and it should clean the virus.

Should this not help, I'm afraid the only other alternative would be to reformat the HDD and reinstall XP again from a bootable disc.

Hope that helps..

May 07, 2008 | Computers & Internet

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