HP Compaq NX4820 Maintenance And Service Manual page 156

10. Remove the five silver PM2.0×5.0 screws that secure the
base enclosure to the computer.
11. Lift the base enclosure straight up and remove it.
Removing the Base Enclosure, HP Compaq nx4820 and
Compaq Presario V2400 Models Only
Reverse the above procedure to install the base enclosure.
Maintenance and Service Guide
Removal and Replacement Procedures
5–43