Unable to log into other accounts

[Sharkman]

I'm having a strange issue here...

 

Head asked me to bring some laptops from one school to the other in our trust. I disconnected them from $domain1, left School1 and went to School2. I've then gone through the process of joining them to $domain2 instead and they've all been fine except one laptop that is stuck trying to log in to Administrator@$domain1 but won't let me switch user to the local admin account.

I've tried using a command prompt from system recovery to change dontdisplaylastsignin in regedit (or whatever is it) but that's not there and even enabling the built in administrator account hasn't done anything for me.

 

I think I'll have to take it back to school1 and sign in but has anyone seen this before?