Does anybody know what has happened and what I can do to get his program running again?ya, you could try debugging it
Seriously, your post gave no useful information that would help anyone help you.
Did you check Task Manager to see if it's running? Also, add in some logging to see where and when the app stops.
Everything makes sense in someone's mind
public class SystemCrasher :ICrashable
In addition, an integer field is not for irrational people