Have you tried clearing the CMOS? There is a jumper on your motherboard labelled something like CLR_CMOS, which resets all the BIOS settings to default. The jumper is by default set on pins 1 and 2. You need to shut down the PC, move the jumper from pins 1 and 2 to pins 2 and 3, wait for about a minute, then set it back to original position. This will reset your BIOS settings, hopefully resolving the issue. If this is too complicated for you or you cannot find the jumper, there is a circular battery on the motherboard. Unplug your PC's power, remove that battery for 10 minutes, then put it back in. It will have the same effect.