Throw me some ideas here, been dealing now and then with an odd, dodgy issue: on occasion, during POST the motherboard will respond something along the lines of "bad or incompatible checksum" and then proceed to check the HDD, floppy and USBs for a BIOS version to revert to - typically a hit of the reset switch, and the borad will POST normally. But then, on occasion, I run into an issue booting into WIN - either it resets during the GUI screen, or it'll reset when it gets to "loading personal setting" - on very rare occasion, the system will reset long, long after you're entered the boot session; and other times, not at all even with the rig running 12+ hours. Othertimes, the SYS will lock up, but this only tends to happen when gaming. I thought, perhaps it's a bad OC, and reverted back to 3.4GHz with known good settings - still happens intermitently. I've loaded BIOS defaults, and run everything stock, and it'll still act up now and then . . . I considered a corrupted XP install, but that wouldn't explain the hiccups during POST; I've run memtest as that seemed to be the next usual culprit - no issues there . . . So . . . possible bad / failing PSU? Although, all voltage sensors reported through software on the mobo seem to check out alright, I'm not eliminating the possiblity of the unit as failing, especially considering the rather random inconsistent nature of these crashes and failures . . . Possible corrupted BIOS or a corrupted BIOS chip itself? What other ideas can y'all throw at me on this one?