Hello,
I ran across this thread in the process of trying to track down the answers to some of my own problems with the new Windows 8 Remote Desktop.
In reading Prakash's original question and subsequent comments and questions in the thread, I had some possible answers from what I've learned trying to fix my problem.
First, it makes a big difference in whether you are trying to remote into another computer from your own (your computer will be the client), or whether you're trying to allow your computer to be the one that is remoted into (your computer will be the server).
In order for your computer to act as a Remote Desktop server, you have to be running the "Pro" version, and Windows must be registered and activated. Just plain Windows 8 can be a client, but cannot act as a server. Prakash, if you're not running the professional version, that's why the Remote Desktop option is not available in System Properties, and I suspect that even if you are running the Pro version and have not activated Windows you would see the same thing, but I'm not certain about that. I can say from experience that you will not be remote into your computer until Windows has been activated.