Strange Sever 2003 Question

Good Day All -

Not sure if help is available for this, but here goes... We picked up a Windows 2003 SB Server. We're tiny and chose to continue using a workgroup and not a Domain. We ran DCPROMO and de-promoted the domain controller as the last in the domain. We were then able to change the workgroup accordingly and all was happy and well. Now we are getting a system shutdown periodically. It comes from SBCore and states system must be a domain controller and will shut down in 60 minutes. ??? Tried to run DCPROMO again to remove domain, but according to the wizard we are not on a domain wehich is correct we are using the server in Workgroup mode.
Can anyone shed some light or point me to where we can get some furthe info?

Very Much Appreciated.