You can always change file associations if you want to, regardless of what program created the files.
First, locate the file whose association you want to change (either by clicking the directory where it is stored in My Computer or by using the Search command in the Start menu). Then right-click the file name and select Properties from the context menu. Near the top of the Properties dialog box, find the Type of File section and click Change to change the program that opens the file. Next use the pull-down list to select the program you wish to associate with that file type. If you can't find the program on the list, click the Browse button and browse through your folders until you find it. (It will probably be in a subdirectory of your Programs directory.) Caution: If you associate a program with a file type, the change will affect all files of that type, not just the file you started with. Make sure the program really is compatible with that file type: Microsoft Word, for example, can't play a media file.