[GDH]

Yes, it is likely that they have been overwritten and corrupted.

Try running Recover My Files and click on the Manually Select Options button. Then in the SEARCH tab put a tick in the box for "Search for Lost Files" so that it is the only boxed ticked. Now change the default file size to the size of your biggest MPEG.

Click OK and run this search just for the .mpeg file type. The files will all come out to be the same size, but you may find that you are able to recover more movies this way and then reduce their size later.