Sony Viao, Windows 7, Get A Sound Exactly Like Email Notification Every Hour

I get a sound exactly like email notification every hour. I have turned off every possible source of notification sounds I can locate, but cannot stop this hourly chime. I have noticed that rec task is scheduled hourly in task scheduler but cannot fine any indication that it has a notification button. I can, and do, mute the speakers for most of the day but when listening to audio/movies the sound comes through the speakers loud and clear.