I have a 2000 Kia Sportage that the air bag light wont go off

The air bag and SRS or seat belts are all an integrated and complicated circuit. The circuit is so complicated and includes so many things that there are certified Technicians who make a living going to repair shops and dealerships to fix, test and certify these systems. You may run into insurance ccoverage troouble if anything should happen, eg. Air bag deploys when it should not or does not deploy when it should, and you might be refused coverage.
There is a special tester for the circuit. Usually you can remove and re-install an air bag if you are servicing something else and just need to remove it to get to something. After an accident you genrally have to test the circuit as there are resets and computer relerns. Sometimes the circuit might never drop the trouble code without a special tester checking the system if the bag was deployed in an accident.
You may have to pay air bag/SRS techs to fix the car.

Try to reset the ECU by dis-connecting battery for one minute and see if that resets it.