Your Toshiba A200 laptop's basic input/output system (BIOS) is a basic program powered by a small, black chip built into your motherboard. It stores data that allows your hardware devices to communicate with your operating system. The BIOS can be accessed only while booting up your laptop and is often protected by a password. In the event that you lose you BIOS password, you can recover it by resetting it or by using Toshiba's default BIOS password.
Open the display panel and hold down the power button to turn on the laptop.
Follow the on-screen instructions to enter the BIOS menu while your laptop is booting up.
Type "TOSHIBA" and hit the "Enter" key when prompted by the BIOS menu.
Power down the laptop. Unplug the power cable and close the display panel. Place the laptop facedown and rotate the computer so the front edge is facing you. Press on the battery pack's release levers and remove the battery pack from the laptop. Remove the memory compartment cover and its two Phillips-head screws from the centre of the laptop. Do the same to both of the hard drive compartment covers in the lower right and left corners of the laptop.
Remove all Phillips-head screws from the laptop's bottom casing. Place the laptop faceup and open the display panel all the way. Pry the keyboard cover from the laptop with a flathead screwdriver. The keyboard cover is the plastic strip above the keyboard. Remove any Phillips-head screws fastening the keyboard to the laptop. Place the keyboard facedown on the palm rest and disconnect its ribbon cable from the motherboard. Remove the keyboard from the laptop.
Disconnect the cables extending from the display panel to the motherboard. Remove the Phillips-head screws from each display panel and remove the entire display assembly from the laptop. Remove all remaining Phillips-head screws fastening the top cover to the laptop's base. Disconnect all visible cables from the motherboard. Remove the entire top cover to reveal the top side of the motherboard.
Locate the small, coin-cell battery near the processor. Use a flathead screwdriver to pry the battery from its socket. Leave the battery out of its socket for about an hour to reset the BIOS password.
Repeat this procedure in reverse to reinstall the battery and put your laptop back together.
Wear an antistatic wrist strap while dismantling your laptop. This prevents electrical damage to your motherboard.