Compaq 247320-003 - Deskpro 4000 - 5166 Model 2500/CDS Reference Manual page 114

10. Reconfigure the computer, if necessary. Refer to Chapter 8,
"Using Compaq Utilities," for more information.
11. 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 computer cover and front
bezel.
3. Remove the screws securing the drive cage and slide the
drive cage forward out of the chassis.
4. Attach the 3.5-inch drive to the 5.25-inch bracket and
secure the drive to the bracket with the screws provided.
5. Install the guide screw into the first screw hole from the
front, on the left-hand side of the bracket.