Dell OptiPlex G1 Reference And Installation Manual page 37

Moves to the next field.
or
Moves to the previous field.
or
Cycles through the options in a field. In many fields, you can
or
also type the appropriate value.
Scrolls through help information.
or
Enters the selected field's pop-up options menu.
<Spacebar> or
In the selected field's pop-up options menu, cycles through
the options in a field.
or
Exits the System Setup program without rebooting the
system and returns the system to its previous state—the
boot routine.
For most of the categories, any changes you make are
recorded but do not take effect until the next time you boot
the system. For a few categories (as noted in the help area)
the changes take effect immediately.
Exits the System Setup program and reboots the system,
implementing any changes you have made.
Resets the selected category to its default setting.
Using the System Setup Program 2-3