my check charging system light is on , i have a 2008 ford explorer? on 2008 Ford Explorer

on 11/29/12 the truck was working fine, i drove it to work and back home. one block before i got home i heard some engine noise like i was dragging something under it. i parked my truck asn check there was nothing under it . as soon as i tried to turn the explorer on again , it would not start and i noticed the check charging system light is on. The truck just cranks but it just doesnt seem to do anything but that. I tried to use battery cables but it was the same thing no change? i need help , if anyone can help i would appriciate it.

Asked by for the 2008 Ford Explorer
either you need an alternator and/or battery
1 more answer
Is the belt on it? Is the battery FULLY charged? Might want to start there.