The question and title, allow user add!

I know youtube converts your uploaded video after it's uploaded.
I'm trying to copy the same quality a video has on a computer onto the uploaded version; hopefully you can follow what I'm tryin' to say.
how can i download a youtube video?
How to download youtube videos onto my mac easily, and for free?
I play multiple instruments and i would like to make a cover video of me playing all of the instruments, in one video. I've seen a lot of other videos where its done,but i'm not sure how to do it in windows live movie maker or if it is even possible in windows live movie maker. I think it can be done but I just have no idea how. Please give specific instructions on how or a different program where i can do that.

I have a video in .MOV format, it plays well on my IPAD 2. Now I need to edit it with Windows Live Movie, but the software won't accept this format.

How to convert the .MOV format to Windows Live Movie?

"imElfinBlurayRipper" can't be opened because it is from an unidentified developer.

How do you like YouTube? --
How do you like YouTube?
The YouTube page in download mode does not display.. there are only a few grey squares / shapes on screen. It also appears a new version of the downloader is available to download however when I click on download, a dialogue box appears stating the web address / link could not be found
runtime error closes program? --
When I load the source, i get runtime error. this application has requested the runtime to terminate it in an unusual way. Please contact the application support team for more information.
About making a YouTube video? --
I want to make a "best albums of 2013 " video with albums covers and my my audio talking about the video for uploading to YouTube. I can handle the subtitles part, but have no idea about how to add the album covers and audio to the video.