The best defense against ransomware is having solid backups of all your files.
Then if you get infected, it becomes a nuisance (having to reload) rather than a disaster (losing all your data).
What should you backup? Only what you care about keeping!
Our house has been a Ubuntu Linux shop for several years now. For the very few things that I can't avoid running Windows for, I use Virtualbox virtual machines of Windows 7 and 10.
For anyone still mourning XP, I suggest you check out Lubuntu (
http://lubuntu.me/). The desktop will seem quite familiar and easy to get used to.