viruses

[WrigleyF]

What percent, approximately, of computer viruses actually ruin a computer to the point you have to buy a new one? There must be some viruses that can be destroyed after they've attacked your computer without your having to get a new computer.

[jeremya]

Very rarely to never should you have to completely purchase a new computer. A clean wipe of your system with a format of the hard drive and clean install of the OS in most cases will give you a virus free perfectly performing system. (Some people do this regularly simply to avoid "system rot").
There is a rare case where a virus has overwritten hardware firmware on your machine but this is rather uncommon as in most cases it would not benefit the person who wrote the virus in anyway and would simply render that piece of hardware useless.