that my friend is the elephant in the room that you can't see: you are running a 7 year old OS on hardware specs that are more or less 12 months old. try running XP on a p3 600 with 256 meg ram, hey that was the average PC when XP came out. And run Word 2003, a web browser an email client and see how much you enjoy it. you might not even be able to open the start menu for all the hard drive groaning you'll get..
p3 600? LOL. get with the times. Yea its great going on a long trip in a 1974 VW Beetle but its not as fun and comfortable as my wife's 2008 Chevy Tahoe.
your system runs ok because you are using the "if its slow, then throw more hardware at it' philosphy.
Actually, that never crossed my mind. Systems nowadays, if you build your own, are VERY affordable. If you're using a p3 600, then its your own fault, go wallow in your own sorrow. I have no sympathy for you.
Its not my fault XP is 7 years old. I upgrade my systems to keep up with the times. I'm glad XP runs well on my systems at work. At home, I'm ballin' with a HP laptop runnin openSuSE 11.
Too many people bash XP when its their dinosaur hardware causing the bottleneck.