Wifi was working a couple of hours ago on Samsung Galaxy S5. Deleted and reinstalled some apps. Now Wifi is not on and when I go to settings to turn it on, it stays on "off". In the dropdown menu all options are grayed out except Advanced And Help. Can not even get a list of networks. I rebooted router, but it is working fine. Bluetooth is off (I don't use it) How do I fix this?