Lots of good advice in this thread. One thing I will request is that you don't listen to the Windows developers who tell you to suppress all errors because the

Lots of good advice in this thread. One thing I will request is that you don't listen to the Windows developers who tell you to suppress all errors because they will give away your secret sauce and/or scare the end user. It is never acceptable to pop up a "An error occurred" dialog box and exit with no further clue as to what happened. Even in a security context you need to give the user something that they can Google. Of course it is mandatory to never ever put anything useful in the Windows Event Viewer. Ever. Absolutely forbidden. Only useless messages are ever allowed in there. So many times I've had an application crap out and I check the event viewer thinking this time will be different. It never is.