How do you unlock bios password in hp compaq?

You may have to get a technician to take out the CMOS battery.

Depending on the model, there is usually a pair of reset pads under the memory modules.

Short these out for a second, using a short piece of wire or tweezers.

This will rest everything including all the BIOS settings, password and clock, so you may need to set it back up on restart.

If you are not sure, take it to a technician.