I'm off for the weekend starting friday evening. I'll try to check the board, but no promises.
It may not be your vid card causing all this. Some systems (windows or linux or whatever) just don't respond well to overclocking. It might be, though, cuz sometimes when you overclock your cpu, you overclock your agp and pci slots as well and that could cause some goofiness...
why'd you set the NvAGP to 0? 3 is the "universal" setting.