Dell OptiPlex GX1 Reference And Installation Manual page 85

Facing the left side cover, press the release button (located at the bottom-left cor-
ner of the front bezel) and lift the bottom of the cover, allowing it to pivot up
toward you (see Figure 5-2).
Disengage the tabs that secure the cover to the top of the chassis, and lift the
cover away.
padlock
ring
Working Inside Your Computer 5-3