alarm keeps going off

What is your question?

at times ill park turn off car come back and go to unlock doors with push button and nothing so must unlock with key when I open door no lights come on as if the batt is completely dead. but its not I put the key in the ignition and crank and car will start right upbut alarm activates horn starts honking and lights flash. sometimes I can put car in gear and alarm stops but sometimes it doesn't.