If you have been fan of traditional Microsoft Telnet client then you will be surprised to see that traditional Telnet Client is not available in Windows Vista & 7 by default and you have to manually install Telnet Client to use Telnet from command prompt.
There are many good freeware telnet clients like WinSCP but it will not be available when you are on some public computer or on friends computer in that case default telnet client may become handy. Here is small guide on how to enable Telnet on Windows 7.
How to Enable Default Telnet Client on Windows 7
1. Go To Start Menu and select Control Panel
2. Click on Programs in control panel
3. Now click on “Turn Windows Features On or Off” under Programs and Features
4. Scroll down in displayed list and check Telnet Client and click on OK
That’s’ it, Once windows has completed installation process to you can start using Telnet client.