What's the best method to keep a computer running like new.

My step-dad got a new computer about a year ago and it was a good computer. Now it runs like piss and doesn't start half the time and all kinds of shit. It just gets eaten up with viruses very quickly. He has gotten like 3-4 different anti-spyware programs (which may be the problem in itself), but nothing really seems to keep it running good.


SO... any suggestions? he finally got fed up enough with this one that he bought a NEW one (LINK ) lol. so it will be here today and he wanted to try and keep it clean.