In windows 7 or vista, you want to change what program opens a particular type of file, this is changing the file association. For instance you may want word to open txt files instead of notepad.etc.
This is a nice quick solution.
1) Go to control panel and select “Programs”
2) Once your in the programs section, under default programs you need to select ” Make a file type always open in a specific program “.
3) You will then see the associate a file application. Scroll down to the file type you want to change, in my case it is “TXT, then select “Change Program in the top left corner.
4) You will then see the open with application, simply locate the application you would like to use and click ok. This file type will then open with that application.
Consider this book.