Compaq Evo Workstation w4000 - Convertible Minitower Hardware Reference Manual page 53

Hardware Reference Guide
b. Slide the replacement battery into position, positive side up.
The battery holder automatically secures the battery in the proper
position.
Type 2
a. To release the battery from its holder, squeeze the metal
clamp that extends above one edge of the battery.
b. When the battery pops up, lift it out.
Removing a Coin Cell Battery (Type 2)
Battery Replacement
C–3