The Basic Input Output System (BIOS) on a computer is basic software used to ensure the components work together. Errors typically occur in the BIOS to warn you of potentially serious problems with the hardware. Occasionally these errors can be bypassed. An 8603 error indicates a pointing device connection issue and can be disabled when the mouse still works. Even if you have no computer experience, you can fix this error.
Power off the computer by clicking "Start" and "Shut Down." Allow the computer to stay off for 10 seconds. Reboot the computer. Wait for the BIOS to prompt you to enter the setup. Press the necessary key required to enter setup, typically "F1," "F12" or "Delete."
Enter BIOS and search for "PS-2 Mouse Port" or an equivalent title. Switch this setting to "Disable." Press the appropriate key to save the changes. Restart the computer, and allow it to boot back into Windows.
Log in to the Windows system. Click "Start" and "Programs," and search for "Windows Update." Check to see if any critical updates are available. Install those that are available, and restart when prompted. Reboot the computer, and ensure that the BIOS no longer prompts for continuation due to an 8603 error.