Evaluation copy

We have just taken over a support account.
One of the NT servers (NT4) came up with evaluation copy stuff, and keeps rebooting every hour. Is there any way we can fix this without reinstalling the NT server, (Thus keeping all the old settings, no reinstall on top)
We have sent an e-mail to Microsoft 2 days ago but no reply yet.
I would really appreciate it if you can shed some light on the issue.
Andreas