I have a server running Server 2003 R2 Standard for domain and has a local PC that is running XP Pro. Last night the PC performed automatic Windows updates and rebooted. This morning the user was unable to log in and had the error: "Windows cannot connect to the domain because the domain controller is not available or because your user account is not valid."
The user account is fine. User was able to log on to another computer with no problem.
I checked the server under active directory and the computer name was missing. I manually added back in, but it is not giving it a DNS name, or finding the PC's OS etc. I can ping the computer name from the server and it tests fine.