How do we convert external USB keyboard connection from USB to FFC, Flexible flat cable, or maybe FPC, Flexible Printed Circuit, or else (has not confirmed yet the real) to be as replacement that's used in HP pavilion Laptop ?

 

Most likely, you remove the electronics and duplicate the key matrix. Or possibly trace the flat cable back to a keyboard encoder chip and substitute or bypass that. Or make use of the external keyboard port (PS/2?).

 

I just plug my USB keyboard into my Dell laptop and it works (did that to replace the original keyboard that developed a few dead keys).
Have you tried plugging the USB keyboard cable into your HP laptop?

 

Or am I misunderstanding what you want to do?