it is separate but always back up your data externally (the least to an external drive, preferably something in the cloud) and in this case make sure she is not an administrator and use a browser with add ons (firefox) that will help keep things from downloading in the first place. a good anti-virus as well.

i might reocommend a dual boot instead or just a cheap laptop that you can reimage at the drop of a hat. i recommend macrium reflect, free program, to do so.