Prestashop blank front office or failed to open stream

Today's tip is a real problem that may waste lots and lots of time to just find where the error is !! Prestashop is a php cms that is used to develop E-Commerce websites. Hosting prestashop on a linux/apache server will cause no problem at all, but hosting it on a Windows server causes some problems.
you may find your Prestashop Back Office working properly but front office is Blank !! this problem happens because of Folder and File Permissions.