Did you try clearing your RTC RAM
? Is there a jumper close to your battery on your motherboard? Sometimes this works. To do this you turn off the computer and unplug the power cord. Remove the battery. Move the jumper cap from pins 1-2 (default) to pins 3-4.Wait 5-10 seconds, then move the cap back to pins 1-2. Reinstall the battery. Plug the power cord and turn on the computer. Hold down the <DEL> key during the boot process and enter the BIOS set-up to re-enter data.