![](/images/new-backgrounds/1153178/15317889x1.webp)
Unknown user password
If the computer you are servicing has an unknown user password, follow these steps to clear the password.
NOTE: These steps also clear CMOS.
Before disassembling the computer, follow these steps:
1. Shut down the computer. If you are unsure whether the computer is off or in Hibernation, turn the computer on, and then shut it down through the operating system.
2. Disconnect all external devices connected to the computer.
3. Disconnect the power from the computer by first unplugging the power cord from the AC outlet and then unplugging the AC adapter from the computer.
4. Remove the battery (see Battery on page 40).
5. Remove the RTC battery (see RTC battery on page 75).
6. Wait approximately 5 minutes.
7. Replace the RTC battery and reassemble the computer.
8. Connect AC power to the computer. Do not reinsert any batteries at this time.
9. Turn on the computer.
All passwords and all CMOS settings have been cleared.
Preliminary replacement requirements 37