Open Windows Explorer to a folder that contains a CNC program file.
(Windows XP is a bit different, click here to see what to do)

Single click on a file to highlight it. In the Explorer View menu, click on "Folder Options". Click on the "File Types" tab on the dialog that appears.

Scroll down until you find NC Files, or whatever you called your CNC programs. If you can’t find anything, click on "New File Type" and complete the dialog that appears. Otherwise, highlight the NC Files type description, and click on "Edit".

The following dialog is opened.

Click on "Edit" in the "Edit File Type" dialog (above).

In the "Application used…." Window, type the full path name, enclosed in quotes. For example: "c:\CNC Consulting\EditCNC\EditCNC.exe", type a space, then "%1", including quotes.

Then close each dialog with "OK" or "Close". You can now double click on a CNC filename, and open EditCNC with the file.

For Windows XP:
Click "Start", then "help and Support".
Type "associate" in the search box (without the quotes).
Pick "Associate a file with a program" from the list and follow the directions.