Ubuntu 15.10 stopped using WiFi driver

Question

I have a Dell Inspiron 3543. To get its wifi working, I had to select "Use proprietary driver" and it used to work.

However, suddenly it has stopped using that driver. Whenever I select the driver and click on "Apply", it reverts back to "Do Not Use" and the status says "This device is not working"

I tried using a live boot CD and the WiFi works, but not on my installation. How do I fix it?

Answer 1

I connected LAN and even that wasnt working. So I went into its settings and clicked on reset and the LAN started working.

Then I tried "Use this driver" again and the stupid thing started working again. :)