My apps won't stay up more than a second. Help?

[AC Question]

My Samsung S6 apps only stay on less than a second and disappear. The same with the pull-down "window shade" that enables me to access Settings. I've tried removing and reinserting the SIM card, powering down and waiting, then rebooting, and doing the System reboot by holding down Power, Up Volume and Home buttons and going thru the blue screen instructions. I've also tried taking it off Wifi and then connecting again. Can you please help? I have to drive a town away for a Verizon store and do not want to do that tonight. Thank you.