gearbox noise

can anyone please help me.i was driving along in my golf when all of a sudden in started making a very loud banging crunching noise.it sounded like there was metal rubbing together.as i turned to the right the front end of the car dropped.i turned the steering wheel to straighten the car and the car rolled again.

Probably a CVJ gone, but could be the diff rivets which are a weak spot on 020 boxes.

thankyou for your help