If your ignition on your Chevy will not work the first thing you should do is check your battery. If your battery is low or dead the car will not start. I would recommend jumping your car with another and/or replacing your battery. Any service station will do.
If you can't turn your key, you may need to replace the key cylinder. If it is the spark, check your distributor cap and then your ignition coil. They cap is easy to replace while the other two possibilities are a bit harder.