You can detect a virus on your computer by swing a dead chicken over your computer and reciting your IP address backwards 5 times.

The first virus did not originate in the Philippines

They can vary from annoying, to making your computer completely unusable.

True. I have never herd of a hardware computer virus. (Unless you count that external keylogger on thinkgeek)

Just as you get sick when you get a virus, your computer gets "sick" when it is subjected to malware. Malware is programming that serves the purpose of improperly obtaining information or causing the computer programs to perform functions other than their original design. Malware can take many forms but this should give you an idea. This is why the term virus is used.