Compaq 247320-003 - Deskpro 4000 - 5166 Model 2500/CDS Reference Manual page 37

5. Place the jumper on pins 5-6 of E50 for at least one minute.
6. After waiting at least one minute, replace the jumper on
pins 1-2.
7. Reassemble and restart the computer. Your password is
erased from system memory.
When you restart the computer, and the screen displays a
message that says, "system options not set," you should
verify the system date and time.
8. Establish a new power-on password, if you wish.