M17 black screen and 7 beeps at start up

Hi my son gifted me his M17 a few years back. 12 months ago it shut down and ever since i have been greeted with a black screen and 7 beeps. I have replaced the motherboard the CPU and replaced both the batteries. I have also tried combinations of the new parts and tried the power drain and FN fault finding at startup. Nothing has worked and im at my wits end and my wallet is fast becoming empty. I hope someone has a solution other than what i've already tried and buying a new Laptop.

here is my system config:

Processor:  Intel(R) Core(TM) i7-4900MQ 2.8GHz

RAM        :  64MB

Storage    : 75Gb SSD

                  2 x 698 Gb HDD

Graphics  : NVIDIA GeForce GTX780M

Motherboard  : LA-9331P Rev: 1.0