http://www.dfw.com/mld/dfw/news/12154785.htm

Tucker, an Internet industry executive with a doctorate in computer science, decided that rather than take the time to remove the offending software, he would spend $400 on a new machine.
The number of viruses has more than doubled in just the last six months, while the number of adware and spyware programs has approximately quadrupled during the same period, said Vincent Weafer, a senior director at Symantec, which makes the Norton computer security programs.
Of course this does not prevent them from getting their new machines infected.

Seems like there may be an interesting business opportunity to take these infected PC's off their hands, fix them and donate them or even resell them.