Windows 7 doesn’t provide access to telnet client in default. More than likely this was an attempt to make Windows more secure by default, as Telnet is very insecure and whenever you have the choice you should always use SSH. However, with that being said, you can quickly re-enable Telnet by following these steps:

  1. Start
  2. Control Panel
  3. Programs And Features
  4. Turn Windows features on or off
  5. Check Telnet Client
  6. Hit OK

or just search for windows featuers in start menu

windows-features

 

turn-on-off

After that you can start Telnet via Command Prompt.