How to enable Telnet in Windows Vista
By default Telnet is not enabled, if you type it in command prompt you’ll get the following error ‘telnet’ is not recognized as an internal or external command, operable program or batch file.
Follow the steps below in order to install Telnet.
Click START->CONTROL PANEL->PROGRAMS AND FEATURES
On the left hand site of the screen, click on TURN WINDOWS FEATURES ON OR OFF.
After clicking on TURN WINDOWS FEATURES ON OR OFF a WINDOWS FEATURES box will pop-u. In the list look for Telnet Client and check the checkbox next to it. And click on OK.
After the wait, you may return to the command prompt and start using the Telnet command.