I bought a CD of Ubuntu. Now, if Windows refuses to load or hangs up, I can pop the CD in, set the BIOS to boot from it,
and be able to run on Linux until I can fix the W10.
I have run several versions of Ubuntu, both 32-bit and 64-bit. I was on the Win10 "Insider Preview" program from December 2014 until July 2015. By the arrival of the final relese date, I decided that not only did I hate the implementation, but I also hated the marketing scheme, so I totally removed W10 from all my machines. I was running Ubuntu 15 Studio 64-bit on one machine, and was so impressed with it and earlier versions (they just kept getting easier and easier to use and update) that I swore never to go beyond Win 7 Pro or Ultimate. When they finally go down, I'll be done with M$ as a private residential installation.
BTW, I've been building, repairing, and upgrading PCs for over 20 years, and an individual user in the corporate community ten years before that. I think it was 1982 that I bought my own personal Osborne 1 portable computer.