Administrator cannot Restart or Power down Windows Server 2003

Windows Server 2003 EE SP2

Nothing happens when I use the dropdown menu and attempt to restart or power down the Server.
No error msgs in event log?
Other symptoms ….
Cannot logoff Administrator from dropdown menu
No error msgs?
Cntl-alt-del fails to invoke Task Mgr
No error msg?
Otherwise system is working fine!

This just started 2 days ago around the same time I was attempting to install a sound card driver … maybe a coincidence

Any help welcome … thanks