Debugging and troubleshooting problems in a production environment is always a tricky endeavour. You usually do not have the luxuries of having a debugger that allows you to step through your code and inspect you variables and stack trace. Some of the areas you might look at include the Event Viewer, to look for any error events or the application log files, to analyse any caught exceptions. If the application is crashing and there’s nothing obvious available in the logs, your best bet is to perform post-mortem analysis with DebugDiag/AdPlus and Windbg.