2003 Dodge neon Replace computer?

The fault codes you refer to all have to do with the Evaporative Emissions Control system on your car. Essentially, the car contains fuel vapors from the gas tank and eventually sends them to the engine to be burned. This system has nothing to do with why your car won’t start.

The code relating to your key is the direction to look. SKIM, Sentry Key Immobilzer Module, is an anti-theft system that will keep your car from starting unless a “valid” key is used in the ignition.

Any well-equipped local garage with a decent scan tool should be able to handle this for you. Have the problem diagnosed rather than try to throw parts at it.