If you accidentally delete a page in DNN. Do not worry, you can easily restore it. Once you have a login as a site administrator. Under the Content menu on the left navigation panel. There is a menu called Recycle Bin.
Once you have clicked this menu. Under the recycle bin option. There is a tab for Pages. It will list any of the deleted pages. What you need to do is to tick the checkbox and click the Restore button. That is all you need to do.