Remove the BIOSjumper from the motherboard (look in your manual to find this). Turn on the PC without the jumper and let everything load up. Then turn off your PC again and turn it back on with the BIOSjumper back in.
Laptop:
Turn off the laptop (plugged out). Then remove the CMOS battery from the motherboard (again manual). Wait around 15 minutes then put it back in and boot up your laptop again.