Question : Locked out of SBS 2008

Hi There, we have an SBS 2008 server that has only 1 administrator account on it (Admin) which we can no longer log in as. When we try it brings up the message 'You cannot log on because the logon method you are using is not allowed on this computer'. There are only 2 people with this account password and neither of them have been anywhere near the server recently. How could htis happen? and how do we get access to our server?
Thanks.....

Answer : Locked out of SBS 2008

Seems to me Like it was a group Policy Issue.  Someone ahs Applied a "deny" Log  on locally  GP to the Everyone group. Having a second  backup admin account would  Help as the everyone group  means everyone.  Never use deny and everyone in a  gp or security option.

Only Real Solution was in the end to  Backup Data  and Exchange and  Load SBS from Scratch.  

I wouldnt mind knowing the way around something like this. for future but for now I need to  close the question.