Slick, if you got nephews dumb enough to do that, you need to take crowbar and separate your sister and brother.
My kids would look at me and laugh if I suggested anything to do with chain saw. Your mileage may vary, depending on the intellect of your relatives.
/johnny
Telling someone to delete all the files on their computer is unethical. It is unnecessary to actually do that to know it's a very bad idea.