Assuming Windows 7 is your operating system:-
If you go to Start, Control Panel, Systems and Security, Admin Tools, View Event Logs, Application Logs, Windows Logs, Application, select "filter current log" select "error", select "critical"+ "warning" +"error" , then Windows will filter and list all the errors you system has produced.
Most recent are on top.
Scroll down until you see any FSX errors or errors/warnings that pertain to your issue.
Only by using these tools will you find out what is causing your FSX "application" to error and assist programmers to determine what the issue may be.
Regards.