Dell OptiPlex G1 - Manual (Page 64)

Eject-, Power-, and Reset-Button Removal (Midsize Chassis): Dell ™ OptiPlex ™ G1 Systems
To remove the eject, power, and reset buttons, follow these steps:
1. Lay the computer cover upside down on a flat work surface with the back of the cover facing you.
2. To remove the 3.5-inch diskette-drive eject button, pull gently on the plastic part of the button until it comes free.
3. To remove the power button or the reset button, use a small screwdriver and push in on the two or three plastic clips that secure the button to the computer
cover.
When these clips are released, the button comes free from the front panel of the cover.