A followup to my comment (included in the link above):
There are specific Event Log entries as well as repadmin/dcdiag results to look for:
http://technet.microsoft.com/en-us/libr ... 27057.aspx In addition to the Event Log tests some of the other suggestions mentioned in that link, both for identifying and fixing the problems, could be scripted.
NOTE: You might want to review some of the other Troubleshooting articles on M$TechNet, especially AD related DNS Troubleshooting. Note, of course, their preference for MOM in their discussions
Please post any other articles here that you find helpful. I'm hoping to build a library of 'standard' tests for specific environments - AD, MSSQL, IIS, Sharepoint, etc. If we share templates we can spend more time dealing with/fixing these environments than building test sets.