There are many times when you may have installed a software and accidentally made it the default program for opening certain file types. This is quite common when you install media softwares and image softwares along with browsers.
Unassoc is a small standalone utility that allows you to remove user specific file associations and default to using the global program for the file format.
This button will remain dimmed if there is no user-specific association for the file type, which is set when you use open with dialog for opening a file. Sadly the above program is half useful since it does not have the option to change file associations with applications.
In the past, we had written a simple tutorial to reclaim your files to open in your favorite editor in Windows XP. Windows Vista does not have the same options for Windows Explorer but you can manage file type associations through Control Panel. The trick to change file type associations remains the same as our Windows XP tutorial, except for the change in location from Windows Explorer to Control Panel.
Steps to Change File Association in Windows Vista
Step 1: Navigate to Control Panel > Programs > Default Programs > Set Associations.
Step 2: Select the file type you want to reclaim file association for.
Step 3: Click on the change Program button.
Step 4: Change the open with option from the recommended programs or use the browse button to select the location of your favorite application.