Greetings!

Did you inherit this UAT server or build it yourself?

Before going mad just restore it elsewhere, if successful and the result is a perfect copy of production, you can rule...

try google, it took one moment to find

http://www.microsoft.com/Sqlserver/2005/en/us/express-down.aspx

😀

We had this occur when the service account was changed & the server wasn't shut down cleanly so the the spn was no longer registered correctly.

We had to shut down...