Missing Videos - Requesting Viewer Help

Update: The videos are back!  But I still could use help from viewers.  Please see comments.  =)

I've received several emails from viewers letting me know that videos on certain posts are missing from my blog!
Now I'm not talking about the videos where you click Play, and it says, "This video is no longer available, etc" or just shows 'snow.'  Videos like that have been removed from YouTube -- either by YouTube for copyright issues, or by the person who uploaded the video to begin with, or maybe they closed their account.
The videos I'm talking about are the ones that are totally missing altogether.  Nothing is there.  Just blank space.
I really apologize for this!  I've had many comments and emails from y'all telling me how much the videos have helped in your homeschooling.  And now half or more of each post is just ...gone!

Mostly these missing videos are from posts I created 2-3 years ago.
When I looked at these posts on my computer, I do just see blank space where there was once a video.  When I go to Edit and look at the HTML (code) section, where I have copy/pasted in the embed code from YouTube, the code is still there, but then the video isn't visible when I click back to the Compose section.

http://homeschoolersresources.blogspot.com/2011/01/biology-module-10-ecology.html

Ugh!  I have no idea why this is happening!  I had hoped it was an issue with Blogger, and they would resolve it and the videos would be back!  Yay!  But... that hasn't happened.  Yet?  (still hoping)
The only other idea I can think of is if YouTube has somehow changed their embed coding so that the old codes no longer are compatible with Blogger?  But some videos are still there.  So....??
I really am just guessing here.  I haven't had time to look into it at all.

I will be working on these posts, one at a time, as soon as I'm able.  School is currently going on so it will be awhile before I get to it.  We also usually end up doing some subjects during the summer, and summers are quite busy here as well.  But I will get to it.  
It just may not be in time for some of you. =\
It won't be as simple as pasting in new codes, because for most of these videos, I am not able to remember what I posted.  It will be starting over.  Re-reading the Biology or Physical Science book chapters, figuring out what is needed for each section, then re-searching for appropriate videos for that space.  Hopefully it will go faster than I think.

And if my viewers would like to help out, that would be wonderful!
If any of you have recently watched videos that are now missing, maybe they would still be fresh in your mind and if you researched, you would recognize a video or two.
Or for any post that you would like to help out on.  Maybe the current one your child is doing -- that would help us both!

If you find something you think will fit a post, please email me at homeschoolersresources@gmail.com.
Please include which blog post, and which section the video should go in.

I would appreciate it very much!
Many thanks! =)