What version of LW are you using? The latest versions offer you the choice of putting deleted files into the recycle bin...or did you choose to just completely delete the files??

You could try a file recovery program, some people have had success with these. Have a look at the thread below for some more info. I'm not sure whether the programs mentioned there are compatible with Vista...you could also try searching with Google & see if you can find any suitable programs.
Deleting files from LW library - Don't!! File recovery advice

Good luck!