My board is set to "Enable if No Ext PEG" (another option is Always Enable) for Onboard GPU, and "PEG" for Init Display.
One thing I would like to ask, my board is set to 64M for Frame Buffer Size (default value), I'm not sure if this setting is okay and related.
Thanks!

alas, I am having similar problems.

First I had STOP UNMOUNTABLE_BOOT_VOLUME, which was a super annoying issue because it constantly restarted and only flashed up on the screen for a few miliseconds (no exaggeration). SO I reinstalled windoze. NOW I'm getting MACHINE_CHECK_EXCEPTION 9c, which STOPed my game i was testing my newly installed system on (wwiionline) and crashed every 30 min with same error, MACHINE_CHECK_EXCEPTION. Currently setup is ABIT NF8, 6600GT, 2x 500mb ram, seagate 160GB barracuda HD. The entire system was working fine for about 1 - 1.5 years. Till now. I have no way to find out which part is screwed up. ATM I can't even get windoze to boot it freezes at some NVIDA logo somtimes right before windoze starts, and sometimes it boots right up into XP. I thought it was my HD failing BC of the origional error unmountable_boot_volume, but now i wonder if It could be my ABIT mobo (which at the time I was told was best, allthough the mobo link smellllsfunny). or it could even be my GT 6600!!! Or my mobo could be blowing up so it could be screwing up all these components as we speak!!? Help what should I DO, to find the source, and fix it?

on a side note i am hearing a weird small beeping sound, which i believe was discribed ealier in these posts as a distress becon of the mobo?