I have upgraded my server from NT4 to Win2k and set up AD, but no Service Location (SRV) records are present in DNS. How can I set them up manually, or do I need to remove AD and start again?
First, you should find out if you DNS server is configured for dynamic updates. If you are using the Windows DNS server, that's the way it should be. Next you will want to check the Windows 2000 event log to see why it is not registering all of the records. There should be some indication of some failure. Also, you should check that the FQDN of the server matches the FQDN domain name. That is say the NT 4.0 server was in mycompany.com and the new AD directory name is MyCorp.com. When you upgrade, the server gets the name ServerA.mycompany.com and the domain gets the name MyCorp.com. The server will not be able to resolve its own name correctly and will have a slew of problems like DNS registration and the like. In that case, you will have to start over by demoting the machine (removing the domain) and reinstalling.
Alternatively, if you had an offline BDC somewhere, you could promote that to a PDC and upgrade that after you...
correct the FQDN issue. You can use a tool called NetDIAG.exe from the support tools to check on other causes of not being able to register DNS names. To force re-registration, use IPCONFIG /RegisterDNS form the command line.