Notify sound won't work (Windows 7 and Groupwise 8.0.3)

Has anyone else had a problem with the Notify sound not working? I've never had a problem with it before, but we recently upgraded from Windows XP to Windows 7 and I had Groupwise 8.0.3 installed with it. The sound will play when testing during setup (via the Notify icon/Options/Notify), but it will not play when an email is sent and the Notify box pops up with a new email. I'm hoping someone will be able to suggest a solution.