Originally Posted by
gmcg
It looks like a problem of all Nvidia cards. While you try to overclock the PCI-E bus clock, there is some lock, even clearing of the BIOS doesn't help. Your card doesn't post video at all, the motherboard shows 2d error (video card is not recognized) and then goes to FF. I had that problem with 9800GX2 and then tried 280GTX and 9600GT with the same result - it looks that recognition of the video card is locked somehow, and BIOS reset doesn't help. With ATI cards there is no issue.
Why overclocking of PCI-E in BIOS is not cleared with CMOS reset or even removing the battery for 24 hours - it is another question.
To get rid of situation we need to remove overclocking of the PCI-E bus manually using any ATI card/old Nvidia card or just stop using overclocking of PCI-E at all, IMO.