As far as i know using your last free attempt changes your personal license permanently to the license of the last (with free attempt) used file. So your former created apps a no longer recognized by QV as yours because internal license information has changed!
either you buy a license or you will have to rebuild the files.
therefor you could install qv on a different machine using your freeattempts for opening the most important files
in order to make it easier rebuilding these apps.
hope this helps
