The Captain_Sim.x777.update!Main gauge is known to cause a CTD. So... Using Windows explorer, go to <FSX root folder>\SimObjects\Airplanes\CS_B777-200ER_GE\panel folder and open the panel.cfg with Notepad (backup the panel.cfg BEFORE you modify it!!!). In the panel.cfg go to the [Window00] entry and comment out (add two forward slashes (//)) the gauge02=Captain_Sim.x777.update!Main, 0, 0,  3, 3 line. Like this:

[Window00]
file=bg.bmp
background_color=0,0,0
size_mm=1024,768
window_size_ratio=1.00  
visible=1
ident=MAIN_PANEL
render_3d_window=0
window_size= 1.000, 1.000
window_pos= 0.000, 0.000
gauge00=Captain_Sim.x777.sys!main, 0,0, 1,1
gauge01=Captain_Sim.x777.sound!main, 0,0,1,1,Captain_Sim\777\sound.ini
//gauge02=Captain_Sim.x777.update!Main, 0, 0,  3, 3

This should prevent the FSX CTD.