Warning Lights & Gauges went crazy

1998 Chevey Cavalier Z-24 2.4L w/ rebuilt engine - approx 5,000 miles on rebuilt engine, 140,000 miles on the rest of the car. I drove to work, car was fine, parked & shut it off. Went back 5 min. Later & wouldn't start. Mechanic friend stopped by, decided it was flooded, held down accelerator, car starts. Hurray! Drove home that evening, and warning lights all start coming on. ALL warning lights - ABS, seatbelt, airbag, coolant level, engine, Brakes, everything! At times the RPM & temp gauge would fall to zero & some of the lights would go out, then the gauges would jump back up and lights would come back on. Got home and shut off car. Tried to restart and just gives the RRRRRR sound. Warning lights come on dimly while turning the key. Any ideas on what happened?