BIOS stands for Basic Input/Output System. The function of the BIOS is to identify, test and start basic system components like the hard drive, video card and keyboard. Most modern computers store their BIOS in a ROM chip on the motherboard. Resetting a BIOS may be very easy or very difficult. Depending on the manufacturer it may require disassembling your computer. If you’re not comfortable doing this, take the computer to a professional who specializes in laptop repair.
Turn on your computer and note the BIOS "splash" screen that first appears. It will indicate which function key (often F2 or F8) must be pressed to access the BIOS settings. Press and hold this key until the BIOS settings screen appears. If you missed the chance to press this key in time, the computer will continue to boot into Windows. Restart and try again.
Once you successfully enter the BIOS settings screen, use the arrow and function keys to navigate the menus. Keep an eye out for an option that says something akin to “reset to factory defaults.” If you see this, follow the onscreen instructions to reset the BIOS to the factory settings. Then, confirm your choice and exit the BIOS screen, usually by pressing Escape.
If your BIOS does not have an option to return to factory settings, things are more difficult. Because the BIOS is stored in ROM, it must have a constant power supply to store any changes you make to it, otherwise it would reset every time you disconnected your laptop from AC power. Removing power to the BIOS resets it to factory settings and involves disconnecting a small battery attached to the motherboard. On many laptops, the BIOS battery is easily accessible through a door on the bottom of the unit. Unplug the computer, remove the main battery and touch something metal to ground yourself.
Remove any screws holding the BIOS battery door in place. Then identify the battery -- it is generally a small lithium watch-type battery -- and remove it, taking care not to damage any surrounding circuitry. Let the computer rest for a minute or two to discharge any remaining power and replace the battery.
If your laptop does not have an easily accessible door for the BIOS battery, you may have to dive deeper and disassemble the computer to find it. Consult your laptop manufacturer’s website for information on replacing or removing the BIOS battery for your model.
Disassembling your laptop may void its warranty.