from the posts, i gather that he/she wanted to upgrade the disc brakes on the bike, bought some better brakes, replaced the brakes and at some point or another broke the freehub replacing the drivetrain. i imagine the problem started when taking off the brakes. also a possibility; original braking system was substandard so chose to upgrade and broke the freehub dismantling the braking system from the rear wheel.
also, bought the bike second hand, not from the store. there's no telling what the bike has been through. this project seems like a loss.