For Linux the Youtube-dl tool has been my utility of choice. It is easily installed from the software libraries or from the command line [as: sudo apt-get install youtube-dl ]. As with many open-source programs, there is also a Windows version that can be downloaded and used .. however the Windows install is less straight forward as it requiresg Python install as well first. See http://rg3.github.io/youtube-dl/documentation.html for the how to ..
Alternatively, I have recently stumbled on the savefrom.net website which works from your internet browser window .. so it is pretty much operating system neutral - meaning it should work for Windows or Linux or even Apple computers. "SaveFrom.net makes downloading from the internet convenient and simple. With our help you can download audio, video, and other types of files from various websites and social networks: rapidshare.com, youtube.com, vkontakte.ru etc .."