Here's a troubleshooting tip from a colleague of mine who is a Microsoft field consultant and was trying to install Exchange 2010. The problem was that the Exchange install was failing because it could not resolve the DNS server, which was also the domain controller.
After hours of frustration trying to reboot the server and tweak various settings, he read over the troubleshooting section of the Windows Server 2008 Active Directory Resource Kit and discovered that he could re-populate the records in DNS by stopping and then restarting the Netlogon service on the domain controller. Once he did this, his Exchange install proceeded smoothly. Shows what a good book can do when you need it!