Majoram:

Maybe there's a problem with your board. I would suggest doing a complete reset of the BIOS.
Unplug all cables from the back of the computer(anything that can supply power to the MB), and pull the CMOS battery for like 10 minutes and reset the BIOS with the jumpers if there are any. If not use the back panel reset. Then boot into BIOS and LOAD Factory Defaults.