Google YOUTUBE DOWNLOADER, you can download it from the creator site, but it will still send you to the download site of CNET.COM, so to save you time and trouble, you can just download it directly from DOWNLOAD.CNET.COM.
At the cnet download page, click DOWNLOAD NOW.
If your using Google Chrome, you can monitor the download at lower left corner of the screen.
When the download finish, click the file to install it.
The install window will appear, just click RUN.
Click NEXT
Click INSTALL.
If ask of any add on program either acccept if or decline, I usually click DECLINE.
Click FINISH.
After clicking finish, open your browser (e.g. Chrome / Mosilla) and go to youtube site and find the video you want to download, then play the video, locate its web address, the HTTP.WWW.YOUTUBE/WATCH........, select all the text then right click on the address bar, the click COPY.
Go back to the YTD Video Downloader then hover the mouse pointer to the box with PASTE URL, the link will appear on the box, then you can click download. You can locate the file by clicking the SAVE TO folder.