This is a weird one.
We adopted a system with a single SBS2011 box.
This week it hung and we rebooted it, since then any PC that has restarted cannot log in to the network with the "no domain controller could be found to process your login request" error.
We have been working with Microsoft Tech for hours now and we need a fix, essentially from what i can see is the server is not advertising itself as a PDC properly even though all settings appear correct.
If i try and force DNS reg of the server using nltest /dsregdns i get the error that the server cannot dynamically update the DNS records which i believe to be a big part of the problem.
So, i dont know what to do next, pretty stuck and half the users shouting at me!