You can manually change the default programme that opens particular file types, or set a programme if windows does not recognise the file type. 

An example is .odt files which are created by the OpenOffice Programme. Here are instructions for setting windows to open all openoffice .odt files in Microsoft Word. 

1. If you have received a .odt file by email, download it to your desktop or downloads folder. 

2. Browse to the file and right click on it. This will open a menu - Select Open With - Choose default program.. 

3. Select Microsoft Word. Make sure that the checkbox 'Always use the selected program to open this kind of file' is ticked, and then click ok