User Account issue

Hi MajorGeeks, got a minor problem I could use advice on.

The crux of the issue is that user accounts below administrator access (guest etc) don't function. Tried enabling and disabling accounts, but it doesn't work. This is on the same machine, it's not connected to anything, it's not a network of accounts.

Error message upon clicking on guest account:
Group policy client service failed the logon
Access is denied

Event log general info:
The winlogon notification subscriber <Profiles> was unavailable to handle a critical notification event.
The winlogon notification subscriber <GPClient> failed a critical notification event.

The description for Event ID 0 from source SignInAssistant cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer.

If the event originated on another computer, the display information had to be saved with the event.

The following information was included with the event:

StartService failed with hr = 0x80070422

My admin access account is functioning OK, so that's not the problem. Anyone ever experience something like this, or hear of it?

 

Windows Vista SP2, sorry. And the problem is a recent issue after a PC upgrade.