Missing Video

Very frustrated. I made the mistake of renaming a few videos of my kids in iPhoto (silly me, IMG490 just didn't describe what was going on clearly enough). In iPhoto, you have the option to click on the thumbnail and rename the image. So, I did. Suddenly, I can no longer access those videos. The thumbnails with the previous name are still visible, but they are grayed out. I have searched the computer using every tool I know to use and cannot find the renamed files. I figured if I could just find them somewhere, I would reload them into iPhoto and the problem would be solved. Any thoughts?