Scan the manual for the section with all the jumpers documented. There's a Clear CMOS jumper. It should have a shunt on it (the little plastic shorting-block) covering only one of the pins. Power off ...
OK I have this K7SEM system I built for a friend about 2 years ago. She brings it back saying it won't boot. I check it out .. it won't even POST. Lights and fans, but no display or beeping, except if ...