There are four common categories of solutions to remove or reset a BIOS password and here are the details on how to go about resetting your BIOS password.
Manufacturer Backdoor BIOS Password
Most of the BIOS makers have set a backdoor password on the older computer models. That is the master password for BIOS. To reset BIOS passwords first you need to check the manufacturer of your computer’s BIOS. Most computers have BIOS include AMI, IBM, Award, and Phoenix. These are the most common BIOS. You can unlock your locked BIOS using this master password. It works, no matter what the user sets the password to. Many popular computer and laptop manufacturers such as HP and DELL lock the BIOS because they want to protect their machine’s most sensitive areas (those areas which have warranty) from their customers. These passwords are usually used by computer technicians for testing and repairing.
Reset the jumper that holds the password
Open the computer and locate on the motherboard the BIOS password jumper. The jumper is usually jumper 1 and often labeled as PSWD, PWD, CLRPWD, CLEAR, JCMOS1, CLR, CLEAR CMOS, PASSWD, or PASSWORD. Normally you would have 3 pins and to reset the password you just need to put the jumper on the 2 and 3 pins leaving pin 1 empty. After you move the jumper, turn the computer on to clear the password, then once password removed turn it off and put the jumper back to its original position.
Removing the CMOS Battery to reset the BIOS to default
Switch off your computer, and open up the case. You’ll see a circular metallic silver item on motherboard. This is called CMOS Battery. Remove it carefully, and leave it out for about 2 minutes. This act will remove the CMOS memory which contains BIOS password. Set the CMOS battery back and switch on the computer. Restore the CMOS configuration as default. Your BIOS password has been cleared now.
Using third party software utility to reset BIOS password
To reset BIOS you can use third party software like Kill CMOS which wipes out CMOS, or CmosPwd which is a BIOS utility. Hiren’s Boot CD has a few programs including the above two that will help you to reset the password. Here is a link to Hirens Boot CD website http://www.hirensbootcd.org/. To download the latest version, click on the Download link on the left side and go to the last page. You will need a CD writer to put the content on a blank CD.
How to unlock BIOS Supervisor Password from Lenovo Thinkpad Laptop (no damage to laptop)
I demonstrate how to remove/clear BIOS supervisor password from lenovo thinkpad laptops. I have tested this method repeatedly to clear supervisor password of my personal thinkpad W520 and W510. I have been using these laptop since, with absolutely no problem. Theoretically, this method should work most of the Lenovo laptops. All you need to do is to find the location of EEPROM chip on your laptop (You can google it !).