PRECISION M6800 MEMORY CONFIGURATION MYSTERY

Could use help solving this.

On 6/4/19 turned on Precision M6800. Immediately after the Dell Logo appeared the screen went into a "Matrix" kind of look; red background, white numbers, crazy. Up then came an Error: " Memory configured incorrectly. Please enter setup for memory information details. System Halted!" Eventually had to do a hard shutdown (pressed power button).

Waited 10 minutes tried again, now just the Error as before. Could not get back in.

On 6/5 took to a "reputable" computer repair. After a few hours was told, "Mother Board must be replaced." He didn't know exactly what the problem was but figured would be less expensive than all the labor to track it down.

Then to another repair company on 6/6. "You have a fan not working; the one that cools the Graphic Card. Card is burnt." She could run it for a few minutes and it would "Crash". She wasn't sure about the Mother Board, won't know till we replace $400.00 Graphic Card and the fan." 

So, fortunately I have another Dell, M4600, with 16GB of RAM(4x4G). The M6800 has 32GB(4X8G).  I removed the 4 RAM from the M6800 intending to use in the M4600 (it is capable of supporting 32). It didn't work. Don't want to go into that adventure; so I reinstalled the RAM back in the M6800. Just for kicks I turned it on. I got an Error that the Memory had been re-configured (figure I didn't put the cards back in the same slots) but it turned on fine and it's been on now for over 3 hours with no issues. Graphics card is at 48deg C and CPU at 52deg C (Which is where they'd traditionally been. 

I went to Dell diagnostics with Service Tag (Out of Warranty)and ran the 40min. test; everything passed with flying colors. (There are some Driver update recommendations)

Could the simple process of switching around the RAM have been the solution?

Really could use some help; the answer to this puzzle will directly affect upcoming decisions.

Windows 7 Professional

Graphics Card: NVIDIA Quadro K5100M w/8GB GDD R5

1TB 7200 rmp SATA Hard Drive

Intel Core i7-4940MX(Quad Core Extreme 3.10GHx, 4.0GHz Turbo, 8MB 57W, w/HD Graphics 4600)