Jeff,
I don't use Outlook. How does its window take on the caption of your application? And if it does, doesn't that mean your app is already running?
>I've used this method for some time, but there is one small problem with it. If someone has Outlook open and your main application window appears in the title bar of outlook, it will appear as if you are opening a second instance of the program. Closing Outlook (or whatever program that behaves the same way) will allow you to proceed. I'm going to look into Borislav's solution for this reason.