Re: Serious problem, PLEASE HELP!!
Hi, sorry to hear about your problem. The best thing to do if I were you is just start over. Get back to basics and work inhand with him for a day or two. Establish who's the leader again, maybe try join up (but only if you know what you are doing). Check out 'Perfect Manners' - Kelly Marks, if you need inspiration - I know I keep recommending that book left right and centre, but I can't begin to describe how great it's been for me!
Before all that, I definitely agree with TruStar about checking out his back, teeth and saddle. Its horrible to think of all the horses that are playing up because they are in pain, and we haven't checked.
Once you have complete cooperation on the ground, try having some lessons if you can, or just work on a bit of control in the arena (transitions etc). A lesson or two first would probably be best just to give you somewhere to start, and to get him listening to you again.
When you feel confident to start hacking again, just go out and come back for 5 mins. If he plays up, get off and lead him the rest of the hack!! Keep the walks short, so that you don't have to trek far, but you are not losing by getting off. You are teaching him that you will walk exactly where you want to with him, on or off his back. At the moment he is winning by getting home at his own speed. After a while, he should realise that you are going to make him hack, but also that he will be home soon enough anyway. Keep the walk/hacks short (like 10mins or so) and see if he settles down. When he does, lengthen the route a little until he is just out of his comfort zone, keep at whatever length of time that is, or distance, until he is used to it, and then lengthen it again.
It would mean that you are taking things very slowly (you can always do more school work and lunging if you don't think he is getting enough exercise), but if you can slowly build something with a horse it usually lasts much longer.
Of course, this may not work for your horse at all! Hope it helps, or gives you any ideas any way!
Best of luck. :)