you choose an realy old topic 
Can you share your exact error message, best with the message from windows event log. And also give some informations about your system/hardware.
And in case it started since “purchased the F-16 and X-1A” , have you tried to remove that third-party-mods or tried a start in safe mode (
steam: Stuck on a Loop! Can't get game started - #7 by MichaMMA
store: Keep crashing to desktop - #30 by MichaMMA
) ?
But normaly its more like driver or gpu issues, but who knows.