It sounds like the engine has locked up but to be sure let's use a breaker bar on the front of the engine to see if it turns over. check out this video at 16:28 it shows what you need to do:
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.