Default Programs Editor makes it easy to fix file association settings in Windows, including context menu items, icons, and descriptions. Also: autoplay settings and default programs settings ...all without fiddling around in the registry.
File type properties
Context menu editor
Autoplay settings & Upgrade for 'File Types' options from Windows XP
Default Programs associations
...not exhaustive :)
Add, edit, and remove context menu items
Edit file type icons and descriptions
Change the 'Open with...' programs list
Change an extension's associated file type
Add, edit, and remove autoplay handler programs
Disable "Search web for unknown extension" dialog