VB Script scheduled task for shutdown not prompting

I have a vb script that was pushed out as a scheduled task to prompt users for a shutdown of their machine.  If they click yes to the message box displayed it shutsdown the computer, if they click no it snoozes for 2 hours.  The script works great if an admin is logged on, however when users are logged on it does not prompt when run as a scheduled task.  You can manually launch the script and it will prompt but it won't when it runs as a scheduled task.

In testing I've given the users access to scheduled tasks in the control panel and also access to the vbs script.

Originally I thought it was because they could not see the scheduled task it would not prompt so i granted rights to C:\windows with a test account and it still didn't show the message.  I can provide any details needed, thanks for the help.