Door locks

Assuming the batteries are good in the key fobs and the fobs themselves aren't broken it could be a failed receiver on the car called the body module. After replacement it needs to be programmed by the dealer. You may find its not worth the expense on an old car like that. Hopefully your keys still work in the door locks. Sometimes they are corroded from not ever being used and the keys won't even go in. I haven't been able to lock my Cobalt for years. If that happens to you, make sure your insurance is paid up and don't leave anything valuable in the car.