Wireless Networks NOT SHOWING UP ON MULTIPLE DELL LAPTOPS

It's been a very frustrating two days. Yesterday I encountered a problem on my new XPS 15 9750 where all of a sudden none of my wireless networks showed up anymore and I couldn't connect to the WiFi at all. I tried plenty of things online and after no success called Dell where they asked me to do a couple things as well. They were convinced that it was a hardware issue and to send the laptop back. As a spare, today I received a somewhat new Inspiron 13 5000 series from a friend and again all of a sudden all my wireless networks disappeared and my internet stopped working. I haven't downloaded anything from unauthorized or harmful sites, everything I've gotten is secure and safe. But since this has happened twice in 2 days I'm convinced it's not a hardware issue. Please help.