The Free OS website lists available free Operating Systems. (See links below) http://www.ubuntu.com would be a good place to start.
It is a Linux distribution, but don't get frightent by that, it is very easy to use, even if you have never worked with anything but windows.
you can't
UBUNTU
it is illegal to do this
IrfanView is free software that is compatible with OS products. You can download this software for free online from websites such as Cnet and FileHippo.
Almost all the linux OS's are free you can find them at their websites .
Download Limewire's free version for your computer and you can download all music for free, it also has videos you can download etc. But the police did a sherch on this website OS be VERY VERY careful.
Chromium OS is free and open source! That does not mean, however, that Chromebooks are free.
http://www.rarlab.com/download.htm Select English and OS
You can download free vmware images of operating systems if you search on google. For example there are two good free operating systems, first you can download ubuntu from linux or chrome os.
Legally, some apps (Google Play for instance) has free movies to download.
Linux
Cisco owns the OS. Its Linux so I believe its open source. Try to download it off the website. Im currently working on my CCNA so I got it for free. free