System locks up, need either a fix or a replacement/upgrade?

Hi all

First of all, my specs: (I built this computer about a year and a half ago, it's my first and only build, and it's primarily for gaming)

AMD Athlon 64 3800+ (2.4ghz)
2gb corsair xms ddr2
ASUS M2N-E Mobo
ATI radeon X1900 (512mb)
SB audigy 2 zs
Seagate Barracuda 60GB

A couple of months after I built the computer, it started crashing (freezing) with repeating sounds whenever I would play anything hardware intensive like counter-strike or any other modern game. So I tried a bunch of different things including a memtest which came back with no errors. Finally, I took out one stick (1gb) of my ram and left the other in. This fixed the problem. However, I recently purchased Team Fortress 2 and Unreal Tournament 3, and I've noticed some slowdown from time to time, which is annoying. So, I want to go back to 2gb of ram because I think this is part of the problem.

The point of this post is that I need a recommendation for the "best bang for the buck" 2gb of ram (or 4gb for that matter) that will be compatible with my system. I don't have any specific price restrictions, though I'm not going to be getting anything at the absolute top of the 2gb price range. Also, if you have any idea as to what was causing my problem, feel free to comment on that too, though that's not the point of this post.

Thanks alot

You can get 2 gb of some ddr2 800MHz RAM for about $40 at newegg after rebates.

And yea, figure out what kind of PSU you're using. My old X1650 got fried because I was using the el cheapo PSU that came with the case. I am RMA'ing it, hopefully I can get another...

That would work but you can save about $10 at newegg
http://www.newegg.com/Product/Prod [...] 6820146569