Compaq 247320-003 - Deskpro 4000 - 5166 Model 2500/CDS Reference Manual page 64

To install an upgrade module onto the graphics controller,
complete the following steps:
1. If you have locked the Smart Cover Lock, use Computer
Setup to unlock the lock.
For more information about Computer Setup, refer to
Chapter 8, "Using Compaq Utilities."
2. Turn off the computer, disconnect the power cord from the
electrical outlet, and remove the cover or side panel. If
upgrading a minitower computer, turn the computer on its
side.
3. Remove the expansion board cage.
If you are upgrading the Matrox Millennium-II graphics
controller, skip to step 5.
4. Remove the screw at the side of the expansion slot and
remove the graphics controller board. Go to step 6.