Hi Senna,

There are some possible causes to your problem:

1- You did not install the server as a PDC (primary domain controller). This is a choice you need to make during installation.

2- Your network adapter is not working. Check event viewer under administrative tools for possible error messages.

3- Your connection to the network fails. Check cables, hubs and protocols.

4- You are not logging into the correct domain (the domain where the PDC is located).

5- Your user account does not have permission to enter the domain. Are you logging as administrator ?

I suggest you to check all these issues and if you still got problems, reinstall the NOS and do not apply SP4 until you are sure you can enter the domain.

Good Luck.