Don't worry... I have the answer for you...
Yup, the other day I deleted the user from a domain, but forgot to enable another local user!!! Der brain... So there I am sitting with my head in my hands franticly calling people I knew to see if they had a way of getting back into the PC without blowing it away!!!
After a long hard think, I thought to my self, but what if I can create a user in the Command window!
So I searched the web and found that you can... of course you can...
NET USER Administrator /active:yes
should do it, now add a password
NET USER Administrator *
Job done!!! :)
I felt VERY happy when I rebooted and saw the administrator user at the log in screen....