* New CMOS clearing method *
Step 1:
Disconnect the main AC power by either shutting off the power button on the back of your power supply or simply pulling out the power cable.
Step2:
Wait a minute to be sure all the capacitors and coils have discharged.
To be really safe you can press the power button which will drain the capacitors for sure.
Step3:
Press the clear CMOS button on the back of the I/O panel.
Step4:
Wait a minute to be sure the CMOS has been cleared.
Note: It is also recommended to remove CMOS battery to ensure 100% CMOS clear on Big Bang X & Intel 6x Sandy Bridge MB's. If date/time do not revert to original time of MB manufacture then you didn't get a complete clear CMOS.
Step5:
Restore power to the system.