Hi, there is a program called Youtube downloader on the internet. I have a few versions, but the latest version is obviously better, it allows you to download from Youtube and also Facebook.
If you want to give me your email address, I will send you a copy.
When it's installed, go on to Youtube, go to the video that you want to watch, when it shows the link in your address bar, press the right mouse button on the address bar, copy and paste the link on the Youtube program and click download.
Hope ths helps.
Kenno, November 2010