You might be confused about the fact that you can’t download Youtube Videos. You might have been trying many ways to download videos from youtube and you might have falied. But failures are the stepping stones to succes. So you should keep trying many ways and here is one of them, an easy YouTube video downloading tool.
This trick works only in Mozilla Firefox. With this you could directly download the videos from youtube. This is a Greasemonkey script. So you have to download the script editor. You should install this Greasemonkey. After installing it, go to the following link. https://addons.mozilla.org/en-US/firefox/addon/10137
Click ‘Download Now’ for installing the add-on. You will be able to download FLV, 3GP, MP4 and HD quality videos from YouTube after installing this script.