Security,I put the wrong key in my car and a few weeks later my car just shut down and it will not start I believe it’s the computer but…

I believe the computer on my car has shut down I triedto get a new one but I don't know how to reset or set the computer and I'm not sure if it's my car computer see I put the wrong key into my car I kept hearing ticking noises but I ignored the problem week later I turned my car off to go into the store and tried to start my car back up but when I turned the key my car dint start I took it to a car dealership but they never fixed my car so I'm seeking personal advice PLEASE HELP or tell me how my car can be fix and what will I need and can my car be fix . Any one to give me