I agree, best thing you can do now is tweak, definately try defragging. Also you can try going to pcpitstop.com and running their full tests, pretty handy for pinpointing bottlenecks and little things that might be overlooked.
If you just want it to load faster.... And You don't mind reformatting. I'd get a new hard drive. I recommend Seagate Barracuda or Western Digital Raptor. They both spin at 10,000 making data processing much faster. Only costs like 140 dollars for the hard drive if you get a 74gb I also recommned going to like 2.8+ ghz
my dad thought of getting a new hard drive, but we just put in $100 for the ram and a ----load of other thinks that arnt for the computer. and for getting a new processor i dont know where the hell it goes or what it is. i do have a decent graphics card but i think its a lil out-dated.
