A user's workstation is reporting inaccurate system date/time and the issue persists after replacing the CMOS battery. Your initial theory was that the CMOS battery needed replacement. Given that the issue remains, what should be your NEXT step in troubleshooting?
Perform a BIOS update in the hopes that it will correct the issue.
Examine the motherboard for faults or damage that might be causing the problem.
Escalate the problem to the vendor immediately.
Replace the computer, as it is indicative of a failing machine.