You need to share more info. Does it crank, or click? Do the lights work? Any accessories like the radio come on?
It does sorta sound like the switch if you get a check engine w/o the key.
If you decide that the electrical side of the switch is bad, I'll sell you a brand new one for $10 + shipping if you want it. Long story short, I had to buy the whole assembly and ended up with an extra part. Give me your zip and I can add it up.