If it's a manual, could you push start it. After it's started, you could use the key to engage the starter for just the briefest time. This would rotate the starter just a little. Then shut the car off and try to start. If it works, you've got a starter with a burnt out segment, start calling around for a new one. This all assumes your starter solenoid is working. I'm guessing it is because you didn't say anything about hearing the starter whine but not engage.