How to Clear the BIOS & CMOS With Jumper
By Alan Sembera
When you can't access a computer because it's protected by a BIOS password, your only option may be to clear the CMOS using the reset jumper on the motherboard. When you clear the CMOS instructions stored on the motherboard, the computer's basic hardware settings return to the factory default and the password is disabled. The specifics for resetting CMOS with a jumper vary by motherboard, but the basic technique remains the same.
Turn off the computer and remove the outer case cover. If the computer is in a tower case, lay the computer on its side for easier access to the motherboard.
Locate the CMOS reset jumper on the motherboard. If possible, consult the manual that came with the motherboard or computer for the exact location. If you don't have a manual, look for the jumper near the battery on the motherboard, although it will often be in another location. The jumper usually consists of a small plastic tab that fits over two pins. On some motherboards, there is an adjacent third pin as well. Most motherboards will have several jumpers for different purposes, so make sure the jumper is labeled "CMOS," "CLEAR," "CLR CMOS," "PSWD" or something similar.
Remove the jumper from the pins. If there are two pins, but the jumper started out covering only one, attach the jumper to both pins. If there's a third pin, insert the jumper onto the middle and third pins. Wait about 15 to 20 seconds, and then return the jumper to its original position.
Turn on the computer to see if the CMOS has cleared. If there is no change, power down the computer again.
Remove or move the jumper, just as before. This time, power on the computer while the jumper is still off or in the new position. Wait a few seconds to give the motherboard a chance to reset the BIOS, and then turn off the computer.
Return the jumper to its original position, and then replace the outer case cover on the computer.
Always touch a metal part of the case or the power supply to ground yourself before touching the jumper or any other part of the motherboard. Grounding yourself discharges any electrostatic buildup in your body, which could damage the motherboard components.
Some motherboards will power up automatically when you reconnect the jumper to the reset pins. If this happens, wait a few second and then turn off the power.
Alan Sembera began writing for local newspapers in Texas and Louisiana. His professional career includes stints as a computer tech, information editor and income tax preparer. Sembera now writes full time about business and technology. He holds a Bachelor of Arts in journalism from Texas A&M University.