ähmmm… PS/2 ??
( source wikipedia )
How old is your PC ? 
In real, I not expected that there are still PS2 keyboards on the planet 
Do you have a usb-keyboard for a test-case ? 
.. it can still be driver stuff, may which MSFS dont like.
Ah, the temperature check is of course important while the game is running. In idle the temps are low.