I was curious to know that how much time has passed since my Windows Server is running. I found nice command to know the start time of Windows server along with other server statistics. Open command prompt and enter following command
net statistics server
As a result some information would be generated. First line contains name of Windows Server and second line contains the time when Windows Server was started as marked in image below.
This command may be used to get information about windows client OS like XP, Vista. In that case it is more useful to use
net statistics workstation