When I install a fresh copy of XP home (bought it from the store.. not a copy) my pc rocks like lightening speed. But when I start installing all the updates, patches & less .NET 4.0 client (As the .NET 4.0 Client seems to bring machine to slow crawl). The pc starts to slow down.. like there is more resources to watch or something in the background is happening.

So could I not get away with a awesome virus protector & awesome firewall set-up and avoid all the patches?

The machine I have is a quad 4, 4gb ram and 2.3 GHZ process. Tons of room and the machine can run several apps at one time.. but when the updates happen.. its s-l-o-w!