Unable to switch to associate window/Modal dialoguebox on IE browser(Application compatible only IE)

I am not able to switch to the modal dialogue box which opens on a screen by the click of a button present inside an Iframe.
I am able to click the button and the Dialogue window opens but not able to switch,also on this dialogie box elements are not identifiable as write click is disabled and Developer tool does not work too .Also i tried switching by Index,Title,Url,control remains on parent window and thus i extract title and index of the parent page and not of the Dialogue box.
Please let me know your suggestions.