Unexpected Shut Down

Got a Windows 2003 Server, running mainly Exchange 2003. Its the top Domain Controller, also has DNS. I was thinking it may be a memory issue, but here it goes.

For the past two days, it has been shutting itself down with no warning signs, nothing in the event viewer except that “The previous Shutdown was unexpected” error. Well, well, it was unexpected to me too, stupid server!

Anyway, everything seems to be on the up and up, I dont understand where it could be. I checked the normal stuff, virus-spyware-spam ect… Nothing. Everything seems to running optimal and almost perfect. But there is something somewhere that is screwing me up.

Does anyone have any suggestions? Thanks in advance!