Graphics problems with Vista Home Premium x64

[1dera3 28]

Is there a better category for this? I couldn't really find one. Anyway...

Story line:

I decided my ol' FIC KT-748 motherboard and AMD Athalon XP 1700+ weren't any good anymore about a month ago, and so I built a new PC.  Not a great PC, more of a "gamers sorta on a budget" PC. Intel Core 2 Duo, Gigabyte G-something-something motherboard, a nice 200 GB SATA hard drive (I've never used SATA before, haha so excited ), and 2 GB GDDR2 RAM running dual-channel.

The problem:

I also got a EVGA e-GeForce 7100GS (256 MB RAM onboard, DVI-out, etc). Then the problems started. With my dad's hand-me-down, 19", 1600x1200 Planar monitor, I hooked it up - and Vista gave me problems. Every 20 seconds the display would shut off and restart displaying a message, "Display driver stopped responding but recovered successfully / The display driver nvkdlm (something like that) stopped responding but has recovered successfully." So I figured, "well, that's no good" so I unhooked it, took the card out, and hooked my display up to the motherboard's integrated, 32MB (shared) graphics adapter. It got the job done, it supported Vista's effects, but all of the games looked bad or played too slow. So today I went out and got me an ATI card - a Diamond Stealth X1550 (basically the same stats as the EVGA minus the NVIDIA chipset). It's doing OK. It's so far done better than my e-GeForce, but is still far from perfect. The screen flickers quite a bit, and it's not the refresh rate, it's the card. I am having bad luck with these cards! I had the latest drivers for Vista x64, I did all of that troubleshooting, and now it still won't work. Unfortunatly I am fairly shy in the gaming community, but not here... so if any of you guys can help me, that would be much appreciated.

Here's a 30-second video of what's been happening... and the flickers on the screen are the actual display, not the camera's refresh rate.

http://img532.imageshack.us/my.php?image=imag0001ck7.flv

Thank you in advance!