How to Fix a Checksum Error

1. Click 'Start' followed by 'Shut down' and select 'Restart' from the list. When your computer starts booting up, press and hold the 'F10' key. Your computer's system BIOS information will be displayed. Write down the information listed in the BIOS, such as the booting sequence for the computer's devices and the time and date. Click 'ESC' and then 'Y' to exit the BIOS screen when you finish recording the information. Your computer will finish booting up and load your operating system.
2. Turn off your computer. Click 'Start' and then 'Shut down' or 'Turn off computer.'
3. Unplug the power cable of your computer and remove the battery if it has one. Take off the outer casing of your computer by carefully removing the screws and sliding the cover off.
4. Find the CMOS battery, which is located on the motherboard. The motherboard is a rectangular-shaped circuit board and the battery is a silver-colored, round-shaped button cell. It is usually resting in a socket directly on top of the motherboard with the positive pole of the battery facing up. Carefully remove the battery from the socket.
5. Place the new CMOS battery in the socket with the positive side facing up. Replace the outer casing of your computer and plug the power cable back into the wall socket.
6. Press your computer's power button. Press the 'F10' key when the computer starts to boot up to enter the BIOS screen.
7. Enter the BIOS information that you previously recorded in the BIOS screen if there are any changes. Change the date and time and any parameters that are different from your recorded BIOS settings. Press 'ESC' followed by 'Y' when you are finished. Your computer will complete the boot-up process.