I think for beginners Qwik MD which a part of VMD package by the University of Illinois can be really useful as it is the most user-friendly, free and runs on windows. It morbidly slows down your windows during it's running time. So please use a dedicated system if possible.
Rajesh, I and my co workers implemented Monte Carlo simulation packages. Please contact Prof. Dr. Ulrich Deiters at [email protected] for having the software.
You asked about MD simulation in the title of your question and in details, you asked about MC simulation so I think you actually need MC method.
If you are in doubt about your method look at this link :
http://cmt.dur.ac.uk/sjc/thesis_dlc/node58.html
The first thing you should figure it out is your domain of work (classical physics or quantum).
Next, you should find a proper simulation package ( of course you can write your own code but if you are working on MC for the first time, I don't recommend it. It's gonna take a lot of time.)
A brief common list of MC packages (both free and commercial packages):