I want to be able to see a preview of a file or folder in the right hand side, some will preview some don't. How can I make it so that everyone that I click on shows a preview?
What exactly are you wanting to do with preview, that you need to know what is inside the folder? There are better programs out there then Windows Explorer.
That is not going to happen with Windows Explorer or any third party explorer. The system has to open the folder, in order to show the contents. That means clicking on it to find out.
If you mean for it to open folder temporarily on "mouse over" it does not seem to be possible, I'v been chasing that since XP.
Large icons of folders with MM content show first couple of pictures as pages in an half open folder and that's it.