Lost image on .mov file

[kastes]

Hello, could someone please help me
I had a .mov video and was trying to convert it to .avi with a few free converters, but they reduced the quality. And now for some reason I cant even open the .mov file, the size on disc is the same, but there is no image just sound while playing on quicktime or on mpeg streamclip. I dont know what happened to that video, maybe somebody had this kind of problem? Im realy new in video stuff...
Thanks guys!

[Chris K]

Did you installed any of the converters you tried? If so, one might have corrupted the quicktime player core.

I would re-install quicktime (mpeg streamclip also relies on it).