Hello,
If my understanding is correct, Server Manager cannot display the server state and gives an error "Could not discover the state of the system. An unexpected exception was found". This is usually caused by servicing corruption in Windows.
If you have a recent system state backup, you may restore the server back to an earlier point. Or, we can run System Update Readiness Tool to scan and fix the system corruption. Refer to the link below.
System Update Readiness Tool that fixes Windows Update problems is available for Windows 7, Windows Vista, Windows Server 2008 R2, and Windows Server 2008
http://support.microsoft.com/kb/947821
Advanced guidelines for diagnosing and fixing servicing corruption
http://technet.microsoft.com/en-us/library/ee619779(WS.10).aspx
If it does not help, we will have to perform In-place upgrade to repair Windows.
How to Perform an In-Place Upgrade on Windows Vista, Windows 7, Windows Server 2008 & Windows Server 2008 R2
http://support.microsoft.com/kb/2255099
Thanks
Zhang