Viruse - Sony Ericsson K800i Cellular Phone

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

Computer Virus will your PC when don't have a proper Anti-Virus installed. Even if proper Anti-Virus is installed and you don't update the virus definitions of the antivirus to latest available ones through the Internet there is chance that your PC might get effected with virus.

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

Computer 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 operating system. When the application is running, this allows the macro virus to spread amongst the operating systems. 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 ( 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 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- DOS. This virus creates a new file with typically the .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 Boot sector viruses generally hide in the boot sector, either in the bootable disk or the 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

Listen up, I have had a pretty bad virus on my computer before where this guy hacked in and created his own user account on my computer! Will, I noticed that my computer was detecting any viruses! Thats because he put a virus on my virus detector, so it couldnt detect viruses! I downloaded a different virus detector and got his viruses off of my computer right away! Try downloading a different virus protecter and try that!

There is a known problem with third-party virus software when using old virus definitions where they will report that the Nikon View CD is infected with the "Nimda" virus. This is caused when using an old virus definition file that had a particular problem. If your software reports a virus, please contact your virus detection software manufacturer for definition updates. For more info, please see: http://antivirus.about.com/library/weekly/aa111201a.htm There are no viruses on any genuine Nikon software CD's.

There is a known problem with third-party virus software when using old virus definitions where they will report that the Nikon View CD is infected with the "Nimda" virus. This is caused when using an old virus definition file that had a particular problem. If your software reports a virus, please contact your virus detection software manufacturer for definition updates. For more info, please see: http://antivirus.about.com/library/weekly/aa111201a.htm There are no viruses on any genuine Nikon software CD's.

There is a known problem with third-party virus software when using old virus definitions where they will report that the Nikon View CD is infected with the "Nimda" virus. This is caused when using an old virus definition file that had a particular problem. If your software reports a virus, please contact your virus detection software manufacturer for definition updates. For more info, please see: http://antivirus.about.com/library/weekly/aa111201a.htm