nishadrox, 

Once in the bios use the Keyboards TAB and Enter Keys to navigate.

:emotion-2:

I don't know if you tried this step yet but I like to suggest pressing the 'Power On' button for 15 seconds to release Static Flea Power by following steps below:

1. Power off system, removed all peripherals, AC adapter and then battery.

2. Press the 'Power On' button for 15 seconds. Replace the battery, adapter and then power on system. Hopefully computer starts normally.

If that step doesn't fix the problem, I suggest you run the diagnostic tool (F12 key) to check hardware on system. Please power on system, quickly start tapping the F12 key continuously. In the menu, stroll down to Diagnostic and click on it. Report back any error code.

No luck. And F12 key is for boot options not diagnostic.

I'm assuming you didn't see the 'Preparing one time boot menu' or boot options as seen in image below ?

  Running Dell F12 Preboot Diagnostics - YouTube

I see the screen. But as I said the keyboard is non responsive after that.

If yes, I suggest you contact Technical Support for further assistance in the link below. Hopefully one of the Dell reps here on the forum, see the thread and be a help to you.

www.dell.com/.../Contact-Information

There's a numlock key. But it doesn't activate the keyboard either. I can access BIOS and boot menu. It's after that the keyboard becomes non responsive.

Anyway possible you can borrow or purchase a external USB or Bluetooth keyboard to test if it responds correctly?

USB Keyboards - walmart.com

On some Dell computers, there's a Num Lock key on the keyboard. If there is one, you can press down on it to see if it will activate the keyboard again. If that doesn't work,try an external USB or Bluetooth keyboard to test if it responds correctly.

Please keep in mind, you can contact Technical Support in the link I've posted above. I also suggest you check the system warranty status in the link below:

www.dell.com/.../