There is a bug, well many bugs on Youtube when using Internet Explorer. This one bug is when managing videos, the "X" or checkmark, doesn't show up in the boxes when you click on them.
I sometimes delete videos that are just not getting any views at all. I tried, the video failed. You can't win if you don't try, right? I checked the video to delete, and then accidently checked the box above all the videos which indicate "ALL" but there wasn't a checkmark in the box. No problem- I didn't actually click it I thought. I then clicked on the pull down menu I meant to click on and selected "delete". Bam.... 100 of my latest videos all deleted in one fell swoop. These videos went back to the end of July 2011.
Fortunately Youtube Partner support was a lot of help and actually restored all 100 videos in less than 24 hours after I reported it them. People may say a lot of bad things about Youtube Support, but hey, they did a great job for me. I didn't expect so much as a reply to my email, so it was a great relief to get the help.