Finally, I've made a breakthrough! I had been struggling to find the right software in order to download and convert video files for my presentation, but finally I have found a process that works quite well! Of course, downloading one program gave me a virus, which set me back a little bit because I had to try to regain control of my computer before moving forward. Alas, I suppose that is all part of that "pleasant frustration" concept!
I have found that the website www.savevid.com works quite well in terms of downloading the video files. Once on the site, I paste the desired URL from YouTube into the appropriate field and select "Download." I then click "Download flv" and save the file to my computer. Now it is time to convert it. The easiest program I found to do this is called "Any Video Converter," which I was able to download for free. I first must choose to convert the vid to the proper format, which is "Customized WMV Movie." Then I click "Add Video," choose the video that I want to convert, and select "Convert" Moments later, I have the ability to import the newly converted video clip into Windows Movie Maker. After all of that trouble, this is a thing of beauty!