Compaq 247320-003 - Deskpro 4000 - 5166 Model 2500/CDS Reference Manual page 40

You can unlock the Smart Cover Lock by running Computer
Setup and selecting Unlocked at the Smart Cover Lock option.
In case of hard drive failure, you can also unlock the lock by
completing the following steps:
1. During POST, press Ctrl+F10.
If you have established a setup password, enter this
password when the prompt appears.
The ROM-Based Setup Utility menu appears.
2. Select the Cover Lock Control option.
3. Select Unlock.
4. Select Save Changes and Exit to exit the utility.
If you enable the Smart Cover Lock and cannot enter your
password to disable the lock, you will need a Smart Cover
FailSafe Key to open the computer cover. You will need the key
in any of the following circumstances:
Power outage
Start up failure
PC component failure (e.g., processor or power supply)
Forgotten password
You can obtain the FailSafe Key by any one of the following
methods:
Contact your authorized Compaq reseller or service
provider.
Refer to the Compaq World Wide Web site
(www.compaq.com) for ordering information.
Call the appropriate number found in the "Worldwide
Telephone Numbers" table in Chapter 9, "Troubleshooting."