So... FSX: SE did work on my computer before. Now it won't start. I click on the launcher, and the load screen comes up (when you first click on it), and then it just... quits. No error messages, nothing. I checked in task manager and it was not running anywhere else. I verified the integrity of the game files on Steam. But it still just quits on startup. What can I do??? 

What have you done to your system between the last time it worked and now?

Something must have changed. Windows update, driver update, new addon or software installed, etc. If it worked one day but not the next then something changed which caused this to happen as it can just stop working on its own.

Have you tried deleting the FSX.cfg and restarting the sim and also tried rebooting the computer.

57 minutes ago, cmpbellsjc said:

What have you done to your system between the last time it worked and now?

Something must have changed. Windows update, driver update, new addon or software installed, etc. If it worked one day but not the next then something changed which caused this to happen as it can just stop working on its own.

Have you tried deleting the FSX.cfg and restarting the sim and also tried rebooting the computer.

I added a new hard drive to my system and it changed the lettering of my drives, as I keep all my FSX files in an external USB drive (E:\) , and the new hard drive I installed changed the letter order of my USB hard drive. I changed the letter back and and used the registry utility to change the path back to the correct location (I verified the change). Now it doesn't work. I'll try deleting the FSX.cfg and rebooting.

 

EDIT: I deleted the FSX.cfg and rebooted. I made it to the main menu screen, which immediately froze and it gave me the "FSX is not responding" popup. I closed FSX and tried to restart it, to no avail... (FSX is not responding) I will try deleting the FSX.cfg once more, and if it does not work, I will try verifying the integrity of the game files.

During the load to the setup screen, FSX loads all of the modules in the dll.xml so I suspect one of those modules is out of date, missing, or corrupted.  If you have no modules loading, then check the AVSIM CTD Guide and look at Page 10, How to Fix Most Freezes/Crashes and Page 27, Application will not Start.