Help! Installing Win 10 in my Inspirion Ultrabook turned wifi off completely!

[WPCentral Question]

Installed Win 10 about two weeks ago. Network connections actually were ok for a day, ie, wifi actually automatically connected to known networks w saved passwords. Then wo an error msg, wifi turned itself off. No option to turn back on. Settings screen does not even give me an option for wifi, other than to turn off Airplane mode. F2 key does not function. Searched "change adaptor settings", "turn wifi on" etc in Settings, only brought me back to the same screen. Restarted x3, no change. Revert back to Win 8.1...? And never try again!