1996 Pontiac Bonneville Car turning off

1996 Pontiac Bonneville

Yesterday, I was driving my car and it immediately stopped. The check engine light came on and my car alert system came on. My car, however was still on (i.E. Engine still on, radio working etc.). WHen my car stopped, my steering also became hard. I took it to a mechanic today and he told me that it was not the transmission, alternator, or battery. The starter is also fine, as when I would attempt to restart the car after it "died" it would attempt to turn over. I was told by someone that the problem might be fuel related (i.E. A clog or something impairing the fuel from flowing). The mechanic however feels that it is not fuel related and the car needs more testing. Can you help me? Thank you.