Making a dialog a top window

Here's the situation. Delphi 7 pro edition.

I need to have a dialog box pop up when an event happens and I
need it to pop the dialog up no matter what application the user is currently using. So, for example, my program is running in the back ground while I'm surfing the web. My program hits it's critical event and I'd like the dialog to pop up on top of the browser, sort of like a system error dialog, that takes precedence over everything.

Any suggestions?  Thanks in advance.