iPhone 4 won't ring

My iPhone 4 has stopped ringing when I get a phone call or text message, it only vibrates. Additionally, the volume control buttons on the side of the phone are not working. The alarm works normally, music plays normally, and the speaker phone works. When testing the ringer or playing music, I can adjust the volume on the screen. The ringer switch is not on silent, but it acts as if it is. The settings are the same as they were when it was working normally.

I have reset and restored and downloaded the latest software... Any ideas?