Turn off the computer and any external devices, and disconnect the power cord from the AC outlet.
Disconnect the keyboard, monitor, and any other external equipment connected to the computer.
To reduce the risk of personal injury from electrical shock and/or hot surfaces, be sure to
disconnect the power cord from the AC outlet, and allow the internal system components to cool before
When the computer is plugged in, the power supply always has voltage applied to the
system board even when the unit is turned off. Failure to disconnect the power cord can result in
damage to the system.
Static electricity can damage the electronic components of the computer or optional equipment. Before
beginning these procedures, ensure that you are discharged of static electricity by briefly touching a
grounded metal object. See the Safety & Regulatory Information guide for more information.
Remove the access panel.
Pushing the CMOS button will reset CMOS values to factory defaults. It is important to back
up the computer CMOS settings before resetting them in case they are needed later.
Locate, press, and hold the CMOS button for five seconds.
Make sure you have disconnected the AC power cord from the AC outlet. The CMOS button will
not clear CMOS if the power cord is connected.
Replace the access panel.
Reconnect the external devices.
Plug in the computer and turn on power.
You will receive POST error messages after clearing CMOS and rebooting advising you that
configuration changes have occurred. Use Computer Setup to reset any special system setups along with
the date and time.
Clearing and resetting the CMOS