Fixed most of my problems (computer related), some to go

I asked previously about a system I built for gaming, and almost all the problems I had are now gone. However, the one that I really hoped to see disappear is still with me. So here is the information to date.

Prior to fixing the problems, here was my system:

Gigabyte GA-EP35C motherboard
Intel E6758 processor
9800 GTX+ OC 512 graphics card
Corsair TWIN2X4096-6400C5 RAM (2*2gigs)
CoolMax CUG 950B power supply
Windows XP Student Edition SP3 for OS
Award Software International, Inc. F2 01/04/2008 is the BIOS version I have.

The changes are that I now have Award Software International, Inc. F4, the Beta version of BIOS (working great, actually, thanks!), and that I now have the full version of Windows XP Professional, as when I updated my BIOS, it shot Windows to Hell and back.

Now, everything is working fine, except one of the problems I had before I updated the BIOS, whenever I play a video game, the graphics often become distorted, and then my computer crashes after a new sound is played. However, it used to loop the sound, now the sound plays on as normal, but the graphical tearing gets worse, until I either get task manager to come up, or I get a blue screen. Sometimes, when task manager comes up, the resolution is normal, and things work as they should; however, about 1 in 10 times the resolution is set wrong, and I get an error message telling me that the NV4 display has quit working, and I am forced to reboot. I have set my graphical acceleration to as low as I can, as was suggested by Windows, but the problem persists.

Any ideas?