How we can create a application like dotnetnuke with the help of MVC. We can add modules and other things directly without modification to code.
As far as I know, there is not any CMS built upon the MVC framework which provides the same flexability and features as DotNetNuke. This is probably due to the fact that v. 1.0 of MVC was only released 4-6 weeks ago.
This type of question speaks volumes. Whilst you will certainly learn a lot by attempting such a project, the fact that you are asking this question suggests that there are many, many gaps in your knowledge, not the least of which is the understanding that you won't get a useful answer by asking such a question due to the fact that such an undertaking is a large endeavour composed of many subcomponents and crossing multiple disciplines. You cannot expect anyone to give you the answers you need in the space required here.
My suggestion would be to step back, fire up Visual Studio and first create a simple website with MVC; perhaps with a few features such as memberships, forums, editable pages and commenting on pages.
Once you feel comfortable with MVC and can find your way around its architecture with ease, you'll be able to start thinking about your approach to more complex problems such as building a CMS like DotNetNuke.
I would encourage you also to not build a new version of DotNetNuke just because it's what you're used to, but to look at that system and decide if that's really the best way to do things and see if there aren't ways you could improve (or completely overhaul) that type of CMS implementation.