Abit latest bios update causing lockups!?

Hello all. I have an Abit IX38 QuadGT mobo that I am very pleased with. However, just a few days ago I installed the latest bios update. Bios ID M704d13, release date 05/09/2008. Using the Uguru bios update feature, the bios installed successfully. If it helps, following is the rest of my config:

Vista Home Premium 64bit
Intel Core 2 Duo E600 2.4ghz (overclocked to 3.0ghz)
Mushkin DDR2 Redline 800 Ram (total 8GB)
Radeon HD3870x2 graphics Card
Thermaltake QFan 650 Watt XFire/SLI ready modular

This is the problem, and it appears to be intermittent. Sometimes while browsing the web, or launching an application my entire desktop will freeze. Nothing will work. I then have to manually shut down or restart my rig. Once restarted everything appears to work fine. My first thought was that I may have a bad ram module, so I ran memtest and after 7.5 hours my ram passed every single test. It has occurred to me that prior to installing the latest bios update from Abit, I did not have these problems, but the lockups have started occurring after the bios update. Could this be related to the bios? If so, can it be corrected (such as reverting to the previous bios)? I am able to boot into my desktop everytime, and most of the time can navigate my browser or work with applications with no problems. As I stated earlier this problem appears to be intermittent.

System temps are fine, there is nothing out of the ordinary that I am noticing, so this is probably quirky problem that will take a lot of time to figure out. I am hoping some of you that are experienced on Toms Hardware with similar problems can suggest a remedy, or get me started in the right direction for troubleshooting. It would be greatly appreciated! Thanks!