In this day and age, I have no idea how people still get virus'
I mean, I'm about as hardcore a porn downloader as you can get, and I'd be shocked if I ever got a virus.
Use noscript, and use common sense, and you are immune from any security issue. Nitpick solved.
My question was more about the performance rather than virus :P
So far we know that the speed (read and write) of the HDDs degrades with the time, Xp loves to put a lot of crap in the registry, and a lot of temp files...
We use CCleaner and TuneUp Utilities, but still, the PCs gets slow with a couple of months of heavy use (We are a bunch of devs, so no viruzes, downloaders, torrents or crap like that, just IDE tools), so yeah, I'm sorry but I can't believe this part "it runs better than when I bought it and it's NEVER been reinstalled", I would like to but I used the same tools and I am not a newbie with this...