Why won't my call screen show?

[AC Question]

Rather I'm making a call or receiving one, my call screen will not show. The only way to end a call is to pull down the drop menu from the top and press end there. When I have an incoming call, it rings and vibrates but no way to answer it. Also, my alarms aren't working the only notify me after that fact that I missed them but don't actually sound. Did I disable something and not know it?