@greyor
Its perfectly legit solution if she only does web browsing. My brother doesn't like Linux, because software he needs for his work (he is electrical engineer) is Windows exclusive. I have same problem as he, thats why I have two SSDs with two different OS, and I only use Windows when I need it for work. So, if your sister also uses some Windows exclusive software then she has a point why she doesn't want to use any Linux distro, why bother?