There are a number of reasons why we might set a password to protect our BIOS from changes. The problem is that we only need to go in there once in a blue moon, making the password easy to forget, locking everyone out.
I had a situation many years ago where a colleague suggested the purchase of a new motherboard because they couldn’t remember the password. I got that little bit more frustrated with my job that day.
There are various options you can use to get back into your BIOS. All of them reset the BIOS back to default values, so make sure you’ve tried all of your regular passwords before attempting these methods. I have tried to keep it brief…
Newer Computers: Most newer motherboards have a jumper on them, which you can change the position of to reset the BIOS. Find your motherboard manual or search for the motherboards model number in Google. You want to find a diagram showing what and where various components and jumpers are on the motherboard. The manual should tell you which jumper needs to be changed.
Once you have changed the jumper, return the jumper back to its original position while the machine is off. You don’t want it to keep resetting itself. Turn on the machine and go into the BIOS. All options will be open to you.
Older Computers: The quickest way to get into the BIOS of an older computer that has been password protected is to remove the battery. The battery keeps the system clock going. Once you remove it, you can put it back in and start the computer.
When you start your computer, you will find your BIOS has been reset to its default values. You are now able to change any settings you want.
General: Some motherboard manufacturers have a secret password that will work, overwriting the password already locking the computer. These are readily available online with a bit of a search. I think this is becoming less common with time.
For more information on the methods above, tech-faq has a great article which goes more in depth.