As far as I know this is a new one. Some suggestions: try deleting the user directories (if one gets corrupted for some reason such as a failed parts update odd things can happen):
c:\users\username\AppData\Fritzing\roaming\Fritzing (which is a hidden directory so you need to enable hidden directories in explorer) and
c:\Users\username\My Documents\Fritzing (where username is your windows id)
If you don't have any parts or sketches you want to keep you can just delete those two directories and Fritzing will receate them, or you can move them aside by renaming them if you want to keep something in them.
If that doesn't work the only other thing I could at the moment suggest is in Friting Help tick enable debugging log which will open a debug window which may provide some illumination (or may not ). Deleting the user directories is probably your best bet though.