IDE :: System Tray / Context Menu Shutdown

I have written a VB.Net Windows Application using VS2003.Net under the 1.1.4322 framework. This application loads a lot of data on startup (about 4MB, taking about 30 seconds) and that data needs to be readily available to the user, so I wrote it to sit in the system tray, using the NotifyIcon and ContextMenu objects.Everything is working fine, even the menu (I have simple options like 'Update' to update the datasets, 'Show' to show the form, 'Hide' to hide the form, and 'Close' to actually close the application).However, when the user attempts to do a Windows 'Log Off', 'Restart', or 'Shutdown', the system refuses.After shutting down every application on the users' computers EXCEPT for my application, the system still refuses to perform the LogOff, Restart, or Shutdown event.In fact, the application I wrote does not even perform it's 'Dispose' method.[code]Therefore, I am convinced that it is my application interrupting the system's process somehow.I have written other Windows Applications WITHOUT the context menu / notify icon objects (apps that don't sit in the system tray) and this problem does not occur.I have also written other applications that DO sit in the system tray, and the same problem occurrs.To summarize this problem: I believe there is something wrong with the way my application is responding to the System events 'Log Off', 'Shutdown', and 'Restart'.This is occurring on Windows XP SP2 computers (has not been tested elsewhere).Could someone explain to me why this happens?? Is there some workaround or some known bug in .Net that causes System Tray applications to interact differently with Windows system events than expected??