How to Unlock a Dell Laptop BIOS Password

By Norm Dickinson

Updated February 10, 2017

The CMOS coin cell battery is located on the motherboard.
i Computer system motherboard image by Timur Anikin from

The BIOS password in Dell laptops is stored with the help of the CMOS battery, which is located on the motherboard. No two systems are alike and the location of the CMOS battery is often difficult to get to on laptops for security reasons. Once located, removal of the battery for a period of time will always reset the BIOS settings to factory default. This erases the password as well as the date and time and resets various other BIOS settings as well. This is normally all that is required to boot to the operating system.

Finding the CMOS Battery

Remove the power cord and main system battery from the laptop.

Remove the hard drive. Check the area for the coin cell battery in the hard drive compartment and in each subsequent step until it is located, and then skip to the battery removal section.

Remove the cover that contains the system RAM.

Remove the optical drive if it is accessible at this stage. Remove all other removable devices such as USB or Cardbus adapters.

Remove the screws from the bottom of the laptop and from the back of the laptop and begin to disassemble the laptop, taking care to track where each piece goes and which screws go in which holes.

Remove the keyboard and the touchpad if necessary. Disconnect the small ribbon cables and other cables carefully and note where they go and how they connect.

Remove the motherboard from the laptop and inspect both sides for the location of the battery.

Removing the Battery

Remove the CMOS battery once it is located and allow the system to remain idle for one hour to ensure the BIOS password has a chance to clear.

Insert the battery back onto the motherboard and reinstall any pieces that were removed.

Boot the computer and follow the prompts to set the date and time and to save settings. No password will be required to boot the computer to the operating system.

Supply the password to log onto Windows.

Items you will need

  • Dell laptop computer

  • Small screwdriver set


The CMOS battery is sometimes hidden beneath a piece of black tape or otherwise disguised but it is always present somewhere on the board. Remove parts from the laptop until the battery is discovered, but do not remove any more components once it is located. The operating system password cannot be reset by this method and must be entered correctly to proceed. To bypass this password the operating system may need to be reinstalled from recovery or restore disks. For best results set up a large piece of paper to set the screws and parts on as they are removed, labeling each one for location and sequence of removal and re-installation. It is often easier and always safer to contact Dell technical support to allow them to handle this type of project.


Laptops are delicate and not designed to be disassembled. Use extreme caution when removing parts as the tiny plastic tabs and connections break very easily and can render the laptop unusable. Many screws are of a particular length and must be replaced in the correct holes. The inner workings of the laptop are static-sensitive and care should be taken to be properly grounded prior to opening the case.