Compaq 247320-003 - Deskpro 4000 - 5166 Model 2500/CDS Reference Manual page 149

6. Remove the blank drive bezel from the inside of the front
bezel.
7. Replace the front bezel and side panel.
8. Reconfigure the computer, if necessary. Refer to Chapter 8,
"Using Compaq Utilities," for more information.
9. If you normally lock the Smart Cover Lock, use Computer
Setup to relock the lock.
To install a 3.5-inch drive into a 5.25-inch drive bay, 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 side panel and front bezel.