HP Compaq dc7600 SFF Hardware Reference Manual page 14

Hardware Upgrades
2-4
To open the computer cover with the Smart Cover Lock engaged:
1. Turn off the computer properly through the operating system,
then turn off any external devices.
2. Disconnect the power cord from the power outlet, and disconnect
any external devices.
3. Use the FailSafe Key to remove the tamper-proof screw 1 that
secures the Smart Cover Lock.
4. Push the metal arm that wraps around the air vent grid up and
back 2 to free the Smart Cover Lock from the chassis.
Removing the Smart Cover Lock Screw
5. Remove the computer cover. Refer to
Cover."
To reattach the Smart Cover Lock, secure the lock in place with the
tamper-proof screw.
www.hp.com
"Removing the Computer
Hardware Reference Guide