Today I wanted to use telnet to log onto the remote server, but the telnet command was not found in the CMD interface, why?
I had to do the same as Oron linked to in order to use Telnet. You have to turn on the feature, and might have to restart the computer if it did not start working immediately. PuTTY is a much better client to use, as Oron stated.
In Windows 7, the Telnet client is not installed by default, but you can add it as explained in http://www.wikihow.com/Activate-Telnet-in-Windows-7. Another possibility is to use a different client (I like PuTTY) which is a more capable client anyway.