On the IBM Thinkpad T42, there are two separate passwords that can function like a normal BIOS password. Typically, a BIOS password must be entered at start-up in order to enter the BIOS set-up utility or to load the operating system. On the Thinkpad T42 a POP (power on password) can be established that must be entered at start-up to begin the booting process. Beyond that, an optional SVP, or supervisor password, can be set to protect the BIOS set-up utility exclusively. According to IBM, if you lose the SVP you'll need to replace the motherboard. The POP can be reset though.
Contact Lenovo tech support and explain your issue. You will need to provide payment information.
Ship the laptop into Lenovo, along with any information provided to you by the technician. Lenovo will replace the motherboard in the system and return it to you.
Test the system to ensure the password is removed and that the computer is functional.
Shut down the computer, remove the power cord and flip the system upside-down.
Slide battery latch A, positioned above the centre of your battery, to the unlock position. It will be marked with an open lock.
Hold battery latch B, positioned to the left of your battery, in the unlock position and pull the battery pack outward to remove it from the system.
Remove the four Phillips head screws marked with images of a keyboard. Set them aside.
Flip the laptop over and open the top. Press your thumb against the raised plastic portion of the keyboard between the "F8" and "F9" keys, then press toward the screen. This will unlatch the keyboard and lift the front portion up.
Slide the keyboard out of the laptop to expose the wire connector on the motherboard. Pull the cable connected straight up to disconnect it.
Remove the coin-cell battery positioned under the keyboard by pulling out the white plastic connector attaching its wires to the motherboard. Set the battery aside.
Plug in the power cord and turn the system on. Allow the system to begin the booting process. When it reaches the point where the password is needed, the screen will not load and the laptop will begin to boot Windows. The password is now reset.
Unplug the system to shut it down. Replace the coin-cell battery. Reconnect the keyboard and replace the screws to secure it into place. Plug the battery back in to its socket and turn the computer back on.