Hmm....Going back to SP2 does not appear to be easy - we found a procedure in a Microsoft library that said you can do it from 'Add or remove programs' but that does not seem to be the case. We have the original OS disk but trying to do it from that came up with some alarming looking warnings and we were worried we might do more harm than good.

In the meantime we've un-installed PT 2012 and re-installed but the problems still remain.