Hi there,
What CPU are you running?
What BIOS version are you using?
What other hardware have you got connected? (HDD's/SSD's, USB devices Mouse, keyboard, etc)
The best way to clear CMOS and re-set everything in BIOS is to disconnect the power supply then remove the motherboard battery for a few minutes. Press the power button on the PC case a few times then put the battery back into the motherboard. Reconnect the power, start-up and go into BIOS. You should need to reset Date & Time if CMOS has cleared properly do this, save and exit. Go back into BIOS and load optimized defaults, save and exit again.