Messed up default application setting on Vista

The default application for graphic files was messed up after I move all my portable apps from one drive to another drive. EVen when I tried to re-register my FSViewer as the default JPEG viewer again and again, the system just didn't register it.

Finally I resolved the problem by opening regedit, and delete all the FSViewer entries. Once done I set the JPEG default viewer again and boom, all is well now.