Actually from what you've listed with no name brands heres some suggestions: Shoot for RAM with a CL2 like Corsair XMS 512MB PC-2700LL, run that RAM by itself the performance will increase unbelievably.
Make sure your hardrive is a 7200RPM, and preferably on the Primary IDE channel as Master by itself.
Any games that you have to have the CD in the CDROM drive to play, get a program that allows you to make a VCD image on your hardrive to run the game straight from the hardrive at hardrive ATA speeds instead of the CDROMs ATA 33 speed, big, big, huge, performance difference. Gamedrive is one of those programs, costs $20 US but theres some guys out here that use a free program, I don't remember the name but they'll probably be along to tell you about it.
Any time you need help in the future list your entire system specs including the P/S wattage, it will give us more information to help you with, Oh and by the way you should be running, with what you've listed around a 350W P/S.
<b><font color=purple>Details, Details, Its all in the Details, If you need help, Don't leave out the Details.</font color=purple></b>