engine fails to turn over

i have a chevey express 2004 5.7lv8 with approx 75,000 it was running the day b4, it was running for about 30mins the next day ,long enough to take my son to the bus stop. however i went to leave and the engine would not turn over,it just kept going errrerrerr i live in n central fl so i do not think it would be weather related could you please assists