Robin, Lee, there is an application called YouTube Downloader. I like to use CNET/downloads, but here is the link as provided on the downloader, plus another through CNET.The home siteCNET site
I just leave a shortcut on my desktop. Any YouTube you want to download, copy the web address and paste it into the downloader. It will save it to whatever location on your computer you choose. I like the fact that it will also convert videos to mp4 and other more useful choices. Haven't downloaded a lot (downside of dial-up) but haven't had any trouble with the few I have ... Ken's instruction video & the concert zither video; a couple of David Summerford's BD; some of Nic Hambas'.
BTW, I never download any 'tool bar' so many applications want to 'add' and haven't had any problems with my virus/spam protection as CNET warns you might.