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How do I clear a BIOS password?

There are two areas in a which a BIOS password could prevent access, in the first the password only prevents access to the SETUP area. In the second scenario the password prevents you from loading the operating system.

Some BIOS have master override passwords, such as AWARD_SW on Award 4.50, if you can find one for your BIOS (exact version) then you are set, all you have to do is type it in and away you go.

Other than that in the first case there are several things you can do, firstly try to find a BIOS password retrieving utility. Depending on the manufacturer of the BIOS, either an exact password or one that will work will be presented to you. You then just type that in when prompted. Alternatively it may just give you the option of disabling the password!

The above approach depends the manufacturer of the BIOS, not all are supported by password utilities. If you are in this situation there is a program called KILLCMOS, which does exactly what is says on the tin. All your settings held in CMOS memory will be cleared by it!
This program is available on a boot disk (called TechW0rm) available from the download page of The W0rms DOS Software Page. But be warned all your settings will be lost, the HDD parameters, display information you name it. This will have to be re-entered, which isn't too much hassle with newer BIOS because they can auto-detect most of the information, older ones however...

So what if you can't load an OS? You will have to open the case, please observe all the usual precautions if you choose to do this, I take no responsibility for any injury or damage.

Get the documentation for your motherboard and see if there is a jumper which can be used to clear the CMOS memory, if so use it.
If you can't get the information about the motherboard, or there is no suitable jumper, you will need to remove the backup battery. You will have to leave it out for quite some time, maybe even overnight. When you replace it and restart your machine hopefully the settings will be cleared.

Do not short out the battery!

Some BIOS crackers, KILLCMOS and master override passwords are available at Packet Storm

For advice on finding/removing the battery look here: How do I change the backup battery?

Copyright © Jonathan Fox 2001.