It has become very simple to set a particular file type to be opened with a specific program or even making an application as a default for handling certain tasks like say web browsing, opening text files and so on in Windows 7 due to the one-stop interface for setting default programs.
To do this, go to Control Panel > Default Programs.
Click on the “Set your default programs” link.
This will open up a new interface from where in one can set a default browser, a default media player, dvd burner, text editor etc.
It is also possible to associate specific file extensions to be handled by certain programs.Suppose if Wordpad is to be used only as a default program for opening rich text format files (.rtf extension), it can be done by selecting Wordpad from the list and then “Choose defaults for this program”.
This will bring up the specified file extensions that will be handled by Wordpad as a default text editor, simply check those file types that you want Wordpad to be associated with.
Same goes for other applications too, pretty simple and everything under one roof .[Remember pre Windows 7 days when one had to at times press Shift and left click to get to the Open With option ]