Control remote computer

Hello everyone!

I hope I'm on the right place to ask.

I'm new to network programming in Java.

I've read some quick tutorials about this topic.

I wanna start with a very interesting project.

One program (let call program A) runs on one computer (let call computer A). One program (let call program B) runs
on another computer (let call computer B). The computers are connected in LAN network.

Program A sends a request to computer B. This request is about locking computer B's keyboard (or take a picture of screen shot of computer B). After getting this request, program B send a feedback to computer A, and
there will be a window on computer A with a CAPTCHA to ensure that the response is generated by a person. After the person on computer A side enters the captcha, let say the computer B's keyboard will be locked.

I guess my explanation is clear.

So please give a quick tutorial or any sugesstion to get me started writting code.

Any help would be greatly appreciated!

If your computer is connected with Internet through broadband router than you can control your computer by the Internet. Virtual network computing protocol and Local area network are also used to controls other computer.