I bought a used built PC for my daughters birthday. I got it home and everything was working fine. It needed a deep clean so I set it aside for a week or so. Last night I tried to boot it up and I got a CPU fan error. The CPU fan is working. In the bios it shows fan speed as N/A but will occasionally show it in the 20's for a few seconds and back to N/A. I tried another PMW fan and the same error happens. If I disable the CPU fan in bios it just boot loops. If I set the CPU fan to DC I get the same error. On a different platform some suggest that the DBMS (database management system) was deactivated and is willing to help me deactivate it for $30. I've never heard of this. Does anyone know of a different fix?