Dell XPS 8930 Service Manual page 104

Procedure
1 Locate the CMOS reset jumper (CMCLR) on the system board.
NOTE: For more information on the location of the CMOS jumper, see
2 Remove the power cord.
3 Remove the jumper plug from the password jumper-pins (PSWD) and connect it to the CMOS jumper-pins.
4 Wait for 5 seconds and then replace the jumper plug to the password jumper-pins (PSWD).
Figure 43. Clearing the CMOS
1 jumper plug
3 password jumper-pins (PSWD)
Post-requisites
1 Replace the right side-cover.
2 Follow the procedure from step 9 to step 10 in
104 System setup
"Replacing the power-supply
"System-board components".
2 CMOS jumper-pins
unit".