Checking to see how long Windows 2000 has been up?

 
This can be done by using a command line utility called uptime. You can also use it to check for remote machine.

Uptime [server] [/s ] [/a] [/d:mm/dd/yyyy | /p:n] [/heartbeat] [/? | /help]
server Name or IP address of remote server to process.
/s    Display key system events and statistics.
/a    Display application failure events (assumes /s).
/d    Only calculate for events after mm/dd/yyyy.
/p    Only calculate for events in the previous n days.
/heartbeat   Turn on/off the system's heartbeat
/?       Basic usage.
/help  Additional usage information.