Hi there,
I have the same problme with Europa Universalis 4. Since the release of version 1.8.1.0 if I run the trainer with it, I get the Windows message saying "there is a problem" and it closes. If I run the game without the trainer it works fine. I have reinstalled the game on Steam to no avail...any ideas? I have had no problems up to this...
Are your programs running with administrative privileges?
Does your AV logs show that it's performing actions that cause the game to close?
You're not supplying enough information for anyone to tell you anything other than go through the troubleshooting guide.