iPhone 4 will not ring. Please help

My iPhone was working fine.  It stopped ringing when a call comes in.    I also do not hear the rings when a test or message comes in.  I can hear the ringtones from the speaker.  The alarm clock works.  The darn thing just won't ring.  The first time it happened, I powered it off and it worked fine for a few hours.  Now, it want ring.  Someone please tell me what to do.  Do I need to reset the phone?  It's backed up to my computer and iCloud.

Settings under Sounds:

Vibrate - Off

Ringer and Alerts - High

Change with Buttons - On

Vibrate - Off

Ringtone - I've tried each one