Dell XPS 8500 (Early 2012) - Manual (Page 126)

• CD/DVD/CD-RW Drive — The computer attempts to boot from the
optical drive. If no disc is in the drive, or if the disc is not bootable,
the computer generates an error message.
• USB Storage Device — Insert the memory device into a USB connector
and restart the computer. When F12 Boot Options appears in the
lower-right corner of the screen, press <F12>. The BIOS detects the
device and adds the USB flash option to the boot menu.
NOTE: To boot to a USB device, the device must be bootable. To ensure that
your device is bootable, check the device documentation.
• Network — The computer attempts to boot from the network. If no
operating system is found on the network, the computer generates an error
message.
Changing Boot Sequence for the Current Boot
You can use this feature to change the current boot sequence, for example, to
boot from the optical drive to run Dell Diagnostics from the Drivers and
Utilities disc. The previous boot sequence is restored at the next boot.
1 If you are booting from a USB device, connect the USB device to a USB
connector.
2 Turn on (or restart) your computer.
3 When F2 Setup, F12 Boot Options appears in the lower-right
corner of the screen, press <F12>.
NOTE: If you wait too long and the operating system logo appears, continue to
wait until you see the Microsoft Windows desktop. Then shut down your
computer and try again.
The Boot Device Menu appears, listing all available boot devices.
4 On the Boot Device Menu choose the device you want to boot from.
For example, if you are booting to a USB memory key, highlight USB
Storage Device and press <Enter>.
System Setup Utility 126