Seldom Drive, Won't Start, Check Engine Light (first COVID now THIS???)

My wife and I just moved to New York five months ago (great timing, right?).

We rarely drive our 2013 Prius C. Once per week for several months. Then COVID hit 6 weeks ago.
So now every other week we loop the block. Two weeks ago it drove around the block fine.
Had 1/2 to 1/3 of a tank.

Last night I tried to turn it on and it powered up, but the radio display wouldn't turn on. I tried to turn it off after a minute or so, it wouldn't turn off. Tried again, no luck. Finally it turned off. I turned it back on again. Now the gas showed as 0 bars. The battery showed as 2/3rds full. The radio display still wouldn't turn on. The engine was making a kind of hum. Seemed weird. I turned it back off and opened the door. The locks would lock, but not unlock. I turned the car back off. I turned it back on. Now none of the dash lights up, just the check engine light comes on.

I turn it back off. I get out and then lock and close the door. I make sure the FOB still unlocks the car. It does. I go to bed because it has been a hell of a week.

So now it's day time and I need to deal with this. I have no mechanical experience or knowledge. Any help would be immensely appreciated. I'll start reading through the manual to see what it suggests, but I'm assuming this community is going to be a good resource. Thank you in advance.

 

I should have included that. 100k miles. No repairs had or needed. Got it checked before we moved. Always changed oil on time. Also did safety and emissions in January and no problems.

 

I will call around to find a place and get it checked. Thank you.