Windows 2k server not shutting down

I have Windows 2k server with service pack 3.
It is a file a print server. When I try to shut it down, it does everything correctly (saving settings etc)but it does not restart. It stays at a black screen with a blink cursor in the upper left hand corner. And I have to hit the power on button in order for it to come up? It use to work fine, and nothing new has been installed. except some security patches.