How to set Default program extension for opening a file?

[ModeratorNA]

If a program does not show up in the list, you can make the program a default by using Set Associations.

1. Open Control panel, and select Default Programs by clicking on it.
2. Click Associate a file type or protocol with a program.
3. Click the file type or protocol that you want the program to act as the default for the file type.
4. Click Change program.
5. Click the program that you want to use as the default for the file type you selected, or click the arrow next to Other Programs to show additional programs. (If you don't see Other Programs, click Browse to find the program you want to use, and then click Open.)
Click OK.
(Note: Above process is applicable to Win 7)