So, you want to see the date and time a Windows Server 2008 box last booted up. From a command prompt run:
C:\> systeminfo | find "System Boot Time" System Boot Time: 17/12/2009, 23:09:04
You will then be shown the date and time the server was booted (as seen in the example above).
You can just run “systeminfo” on it’s own (with no ‘| find “System Boot Time”‘), and you will be presented with a lot of other information such as Hotfixes, Network Connections, etc.