Local users cannot logon

My local users when they try to logon get as far as the logon script which hangs at the end. I think that the SAM for my domain may be corrupt but I do not know how to repair it, can anybody help? We had to rebuild our PDC as it died in a major way.We promoted a BDC but it did not make any difference.
We have a load of remote users who logon via CITRIX and they have no problems at all logging on and running logon scripts