Compaq Evo Workstation w4000 - Convertible Minitower Hardware Reference Manual page 15

Product Features
1–10
4. Disconnect all power and data cables from the drives in the
5.25-inch drive bays.
5. To release the drives from the 5.25-inch drive bay, press the short
yellow drivelock 1 as shown.
Activating the Drivelocks (Shown from the Rear of the Chassis)
6. While pressing the drivelock, pull the drives out of the drive bay.
Hardware Reference Guide