Prepare the computer for disassembly (refer to Section 5.3, “Preparing the Computer for Disassembly,” for more information). Remove the real-time clock (RTC) battery (refer to Section 5.14, “RTC Battery,” for more information on removing and replacing the RTC battery).
Wait approximately 5 minutes.
Replace the RTC battery and reassemble the computer.
Connect AC power to the computer. Do not reinsert any batteries at this time.
Turn on the computer.
All passwords and all CMOS settings have been cleared.