You replaced the system board on an HP PC and receive an Invalid Serial Number error upon booting. What should you do?

Entering the valid serial number in the BIOS using Computer Setup is the correct course of action when faced with an Invalid Serial Number error following a system board replacement. When the system board is changed, it often requires reconfiguration to ensure that the new hardware components communicate correctly with the system’s firmware.

The serial number is critical for the system's identity and authentication, and the BIOS firmware needs to recognize it to initiate the boot process properly. By accessing the Computer Setup (BIOS) and inputting the valid serial number, you allow the board to function correctly within the broader system context, which resolves the error and enables normal booting.

Utilizing the Serial Number option ROM setup utility could be an option as well, but it may not effectively address the need to input the exact serial number required for the new system board, which is essential to resolve the issue. While running diagnostics is a good practice for system verification, it doesn’t specifically address the serial number problem. Downloading and installing the latest BIOS version is generally a beneficial practice but won’t solve the Invalid Serial Number error — it is primarily a reconfiguration issue related to the system board itself.