Dell XPS 8500 (Early 2012) - Manual (Page 127)

Changing Boot Sequence for Future Boots
1 Enter system setup. See "Entering System Setup" on page 119.
2 Use the arrow keys to highlight the Boot menu option and press <Enter>
to access the menu.
NOTE: Write down your current boot sequence in case you want to restore it.
3 Press the up- and down-arrow keys to move through the list of devices.
4 Press plus (+) or minus (–) to change the boot priority of the device.
Clearing Forgotten Passwords
WARNING: Before working inside your computer, read the safety information
that shipped with your computer and follow the steps in "Before You Begin" on
page 13. For additional safety best practices information, see the Regulatory
Compliance Homepage at dell.com/regulatory_compliance.
WARNING: The computer must be disconnected from the electrical outlet to
clear the CMOS setting.
1 Remove the computer cover. See "Removing the Computer Cover" on
page 23.
2 Locate the 3-pin password reset jumper ( PSWD ) on the system board. See
"System-Board Components" on page 21.
3 Remove the 2-pin jumper plug from pins 2 and 3 and fix it on pins 1 and 2.
System Setup Utility 127