[Jack_Kevlar]

Hi,
I just upgraded my motherboard, RAM, CPU, and windows version. My graphics card is the same (Radeon 1900 series) but now my display driver doesn't seem to work. When I play games like Hitman Bloodmoney and Call of Duty 4 the game runs perfect for about 10 seconds then goes into about 5 seconds of intense lag. Like, unplayable choppiness. Then, it runs smooth again for about another 10 seconds, and the vicious cycle repeats itself.
I'm fairly certain it's a software issue because I managed to install my driver right once. All games ran smooth, and I enjoyed this setup for a few days. Then, for some reason, I decided to see what would happen if I let windows update my driver, and the problem came back. Now I can't get my driver to work again. When I start installing my driver, Vista installs its own driver, and Catalyst installs overtop. There's no way to stop Vista from installing its own driver as far as I can tell. The only way I got my driver to work was one time, I finished installing it and a message came up saying 'this program may not have installed correctly... let windows re-install using recommeneded settings?' I agreed to let windows do this and it worked, but ever since I haven't been able to repeat that process with it working.
I've tried installing old drivers, XP drivers, going into safe mode and uninstalling window's version of the driver (it reinstalls itself when I reboot though). Nothing seems to work. Please help me.

Old system:
Windows Vista Business 32 bit edition
AMD Athlon 3700 single core processor
2 GBof DDR ram
ASUS A8R MVP motherboard
ATI Radeon X1900 series graphics card.

I upgraded to:
Windows Vista Business 64 bit edition
AMD Athlon 64 X2 dual Core Processor 6000+
4 GB OCZ DDR 2 RAM
ASUS M2N VM DVI motherboard

Any suggestions would be helpful. I don't know what else to try. Thanks.