Some people asked me about the faster way to know if a server has been rebooted during the last hours and who rebooted it. The answer is simple, search on the server System Log on Event Viewer (Start > Programs > Administrative Tools > Event Viewer or Control Panel) for Events with ID 1074 or 1076.
Doubling click on the event you can see the Reason code, the Comments, etc.:
Do you know other way to check it?
Angel Perez Palacios 