When I install a fresh copy of Windows XP Home (I 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 are more resources to watch or something is happening in the background.

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

The machine I have is a quad 4, 4 GB RAM and 2.3 GHz process. Tons of room and the machine can run several applications at one time.. but when the updates happen.. it's s-l-o-w!