Alarm at 75 MPH
 

I have a 2003 Cavalier. As of two days ago my car started making an alarm sound when I reached 75MPH* on the highway. Once I dropped back down to below 70 MPH, it would stop. The alarm sound is the light ringing of when you leave your keys in the ignition in park and attempt to leave the car. The same day the car locks stopped responding to both key fobs. I don't know if the two are related, but they happened simultaneously. How do I address this issue? Is it safe to drive vehicle?

*I live in a state where 75 is the legal speed.