After Replacing a Failed Mother Board in a User's Computer

After replacing a failed mother board in a user's computer, the technician receives a report that the computer is behaving erratically. The user states the computer shuts down randomly throughout the day and freezes frequently. The technician performs a memory diagnostic, and it reports no issues. Which of the following should the technician check NEXT in troubleshooting this issue?

A) Reseat the memory and reset the BIOS to default settings
B) Add heat sinks to each installed memory module
C) Enable overclocking functionality in the BIOS
D) Ensure all case fans are plugged in and working