Resolution:

To resolve the above error, you will need to remove all references to the Power Users group in the Local Security settings on the affected machine.

1) Click Start
2) Click settings or Control Panel.
3) Go to Administrative Tools
4) Double click Local Security Policy
5) Click Local Policies, and then User Rights Assignment
6) Double click each item under User Rights Assignments to see whether the item contains the Power Users group
7) When you find a policy item that contains the Power Users group, click to clear the Power Users check box and then click OK.
8.) Finally, restart the computer and review the Winlogon.log file and Event Viewer to make sure that the error message no longer occurs.