Computer issues with high quality

I have a great computer with alot of space on it and a lot of great upgrades for gaming... but its always freezing/locking up during games like battlefielld 2/2142 and spider man movie and basically any high quality games (I meet all the requirements and more) and by lock up i mean the game freezes and the current sound loops the only way out is to restart the computer with the button on the tower. Its not overheating (old issue fixed and done with) But me and my father think its our 430W power supply not being able to keep up, or else our 1 GB of RAM. Any ideas on how to fix this? Our budgets tight and i dont feel like spending anymore money on something that wont help.

My Specs

2.4GZ

64processer

1gb ram

currently fully updated

running a windows XP

I hope you guys can help :?

2.4Ghz what?

And 1GB doesnt cut it in todays games.

And do you happen to be having a graphics card.:?

64 processor? AMD Athlon 64?

Usually a system locks up when your card or CPU overheats. Actually, the system usually restart.

And you have the right drivers, right?