One virus can't do anything but when there is dozens, hudreds, thousands it start to really slow down. And usually there is more than 1 virus. Other issue is that I don't want that tracking cookie steals my credit card number.
And reformating is the most annoying thing to do
Thats very true, many times one virus opens up a proxy node for many more to enter. And reformatting can be very time consuming. But people saying that a pc 'dies' because of virus' is a far stretch... Also, I'm using a PC laptop right now that has been run daily for 2 years now with no spyware protection or virus protection at all, with no problems at all... My secret? Stay off of pron sites. When you limit your internet use to trustworthy sites, virus' are not a problem