Since Windows XP the Explorer supports the "Open with" operation for selected files.
The classic "Open" operation uses the associated default-program to open the selected file. In addition the "Open with" operation enables multiple programs to be associated with the same file-type.Example:
Clicking "Choose Default Program..." opens a list of programs, that may be used
to open the selected file.
"Recommended Programs" lists programs that are associated with the selected filetype and are able to open it.
"Other Programs" lists other standard-programs that are registed in the system and may be able to open the selected filetype (or even not).
You can select the program you want to be used for opening the file.
If the option below is checked the selected program will become the new default.
Note: the layout of the screen depends on the Windows version and configuration you are using.
Therefore the screenshots above may not 100% match to your system.
(screenshots are made on Windows Vista with deactivated Desktop Window Manager; =Aero disabled)