Wifi toggle key is not working on Dell Inspiron 15 3542 Touch

WIFI TOGGLE KEY PROBLEM:

I am facing this problem, where the wifi toggle key (with an antea) which sits beside F12 key and shares the Print Screen functionality is not working on my Dell Inspiron 3542 laptop.

The combination as suggested on many websites is "Fn + wifi toggle key". But in my case it isn't working.

When used in conjunction with Win key it works fine and takes a screenshot.

"FN + ESC" PROBLEM:

Also, I am unable to change Funtion key behaviour using Fn+Esc combination.

The two very common alteatives are:

1. Changing the Fn key settings from the BIOS.(Uecessary & a long one)
2. Changing it from the Mobility center.(Easy one)

These alteatives worked well but the "Fn+Esc"(easiest one) problem persists.

Please help me out with this dilemma.