Hello,
I too have the "CTD with no error message" problem with the PMDG777.
I just changed my FSX directory by uninstalling like said in the PMDG forum, and re-installing addons (cleaning up in the process!) afterwards. I changed directory and was on a SSD beforehand but lacked storage space.
Before changing, everything ran fine and I managed to not have any CTD with the 777 (although I had some (mind you, they had Error messages and were from the PMDG777x.dll) in the beginning and managed to solve them) ever since.
But now that I reinstalled FSX, I never could load the PMDG even once.
I tried multiple scenarii : Default flight FSX, default flight with PMDG, loading a FSX flight and switching aircraft, different airports, ... nothing changed :
The loading screen gone, 777's textures start to load their "brownish" structure, and when real Boeing/PMDG textures are about to load, game shuts down without any error (no message, no event in the Event Manager, ...).
I should say that I also have the 737s NGX and I have no issue with any of them, even when loading them right off the bat from "Fly now!".
I tried loading in a different view (Virtual/Cockpit, Outside spot) or livery, and nothing solves the issue. Even from Outside perspective, the game crashes right when it's about to put "colors" on the plane.
I also tried the lag tool you provided and nothing is spiking on the loading, everything stays green.
If anyone can help me with that, that would be very much appreciated, as I really love flying the T7 and am really sad I can take her for her daily trip