Operation Not Valid

[qanda]This thread is about the Liteon LVW-5045. Click here to see full specs[/qanda]My vast library of family videos is inaccessable. ALL my video info is visible ie: video title, running time, protection ON, but ALL thumbnails are gone and replaced with black screens. When I try to play nothing happens. I’ve tried recording existing videos to DVDs and receive the following message “This operation is not valid for the current operation” NOTE: I AM able to record and playback NEW recordings, but ALL previously recorded videos are NOT accessable.