this is an awqward one indeed....
In a command prompt, can only try an ordinary prompt... type the following to try and get the admin account to show...
enter LUSRMGR.MSC (the local user accounts manager)
Accept the UAC warning and continue
Deselect ACCOUNT IS DISABLED
Another option may be to try and create another user in the accounts manager and put that user in the admin group and try log on as that new user and see how it goes...
I still remind one of mine about the milk over the telly incident..