My truck won't start.

Has the battery been load tested? do that first.

check battery volts should be 12.6 volts.if not battery dead.have battery charged and test if battery can be charged alternator faulty.if battery dead cant be charged replace battery.and clean battery cables if EPC warning light still flash have vechicle code scan for faulty accelerator control system or mass air flow sensor.to get vechicle started after replacing battery just turn ignition switch to the on position for 30 seconds then turn off ignition switch then start engine.

What make of car?

Check your battery connections at the starter. It may not be getting the needed volts. Just make sure they're clean and tight at the starter and the battery both. Good luck!

Could be the starter motor.

Multiple issues here??
Why did the motor quit??
Did you check the engine control fuse box for issues? It is next to the battery?
The is an imprinted 'map' under the lid for direction. Check all fuses and relays and post back.

Check the anti-theft module and relay

sounds to me like a siezed up ac unit.. it would not spin while all other pulleys spin... thus causing the broken belt.. hope that helps you

That would make sense, because when he jumped your car if he left it hooked up for awhile. Then he charged your battery up, so it started the next day. Then you drove to his shop and back it ran the battery down. It's easy enough to test and change alternators you could take it to autozone or O'Reillys if there is one close they can test your alternator. If you have more questions about this or if you would like to try and change it yourself just reply to this post and I will walk you through it.

TEST POWER LEADS TO STARTER FOR POWER
AT STARTER (BATTERY POSITIVE TO STARTER BATTERY NEGATIVE TO ENGINE BLOCK)
THEN TEST FOR SIGNAL POWER TO SELENOIDE ON STARTER
(KEY TURNED TO START POWER SHOULD GO TO SELENOIDE)
IF NO POWER TO SIGNAL WIRE CHECK FUSES AND RELAYS
ON STARTER CIRCUIT
IF THIS CHECKS OUT MAY BE AUTO TRANSMISSION NUTRAL PARK SWITCH
TRY TO START IN NUTRAL OR WHILE SHIFTING TRUE GEARS SLOWLY WITH SHIFTER
IF STANDARED CHECK NUTRAL SAFETY SWITCH