If your DNS server's event log contains Event ID 156:
DNS Server does not have a cache (or database) entry for root name server. The cache file MUST have at least one NS record, indicating a root DNS server and a corresponding A record for that root DNS server. Otherwise the DNS server will be unable to contact the root DNS server on startup and will be unable to answer queries for names outside of its own authoritative zones.
you have a corrupt Cache.dns file or the file contains invalid entries.
To workaround the problem:
1. Stop the DNS server.
2. Rename %SystemRoot%\System32\Dns\Cache.dns to %SystemRoot%\System32\Dns\Cache.old_dns.
3. Copy %SystemRoot%\System32\Dns\Backup\Cache.dns to %SystemRoot%\System32\Dns.
4. Start the DNS service.