How to associate monodevelop with unity3d 4.5.2 ?

I am trying to write c# scripts in unity3d game environment. But double clicking the c# script wont open it on monodevelop editor. I tried to change the editor preference but i cannot find Program files(x86)/monodevelop/bin/ after browsing as it seems the whole monodevelop folder is missing. i re-installed unity3d couple of times still it doesnt work. Do I need to install the monodevelop ide separately or installing the unity3d should be enough to make it work? I dont have .net framework installed either, is it the issue?

If you are double clicking in unity: there is an item in the settings menu that let’s you set the default code editor.
If you are double clicking in your file browser: set mono develop as the default program for c# files.
Mono develop should come with unity. I am not sure where it is stored though, maybe in the non x86 program files folder.
If all else fails, use the search function built into windows to find the mono develop exe file.