My laptop is now bricked.  Apparently it is an LCD failure.  It took me forever to find out what the flashing lights on my dell laptop meant as the docs seem to be missing from dell’s support site.  In order to make the laptop do the diagnosis I had to press the blue ‘Fn’ key as it booted.  Then some of the LEDs will either be on, off or flashing (on mine it goes NumLock, Caps Lock, Scroll Lock):

One LED On, Two LED flashing ON FLASH FLASH - No memory modules detected

Two LED On One LED flashing ON FLASH ON - Memory detected but you have a failed module.

One LED flashing Two LED On FLASH ON ON - CPU or processor failure

Two LED flashing One LED On FLASH FLASH On - Graphics card failure

Two LED flashing One LED On FLASH ON FLASH - LCD Failure

Two LED flashing One LED Off FLASH FLASH OFF - Keyboard failure

Two LED flashing One LED Off FLASH OFF FLASH - USB failure

Hope this helps someone!