"Telnet" is a cmd Command mainly used to Control other PC Remotely from any PC.
But there are two condition.....
1.Both PC Must have a High Speed Internet Connection (minimum 1mbps)
2.Target PC should has a Open Port (Like Port 23)
If you don't know about Open Port then Follow My Future Post.
To Enable "Telnet" in Windows 7 follow this >>>>>
1.Open Computer/My Computer
2.Click On ''Uninstall or change a program''
3.Then Click ''Turn windows features on or off''
4.Find and Check on "Telnet client" and "Telnet server" both.