we recently got a 2nd horse.  We're novices. Our 1st horse came to us well trained. Our new horse however, is not.  We have difficulty riding him, he very willingly will follow horse #1 anywhere but doesn't want to go on his own.  so I decided we would do round pen work for a while.  Well, he must have learned (very well) the hook on/latch on concept, he will follow me anywhere and when I try to stand toward his rear he turns to face me.  we begin to go in tiny circles.  I've tried with and without a lunge line and just can't get him to go forward.  I did put him on a lead line and walked and trotted him around thinking he would get the idea, but he didn't.  Can anyone help?

 It's a bit complicated, but a good start is just to get him moving away from you.  A rope or stick in hand will be a big help.  Just toss the loose end of the rope at him to get him moving away from you.  If he tries to turn and face you, you just have to be quicker than him so that you stay at his flank or haunch and driving him forward.  It will be easier without a longe line to get tangled up in.  You may have to do some running at first to stay behind him, maybe pick a day that's not super hot!  Timing will be everything to keep you behind him and keeping that cue on him until YOU  want him to stop.

Reading your post was interesting, you freely admit to being a Novice and I think you are missing the signals your new horse is sending you.

Have you read Monty Roberts and the Join-up principle - your new horse, I feel, is insecure thats why he follows, he is looking to you as the "Dominant Mare" he is trusting you to show him the way - he doesnt know how to lunge and you need to teach him

So having said that YOU need to be more forceful in what you want - send him away from you when he comes in on you - be positive and strong in your actions, he is to move away from you and follow the track of the round yard, get yourself a lunge whip to make the extension of your hand, there is no need to touch him with the whip at all, be sure and make all your "instructions" to him clear and precise so there is no confusion.

It shouldnt matter if he is on a lunge line or not the result should be exactly the same.

Transfer your confidence to him when riding too - he needs to be able to go out on his own and feel secure that you are in control.

Good luck

 AMM, you hit the nail on the head. 

He may be insecure, but he may also be avoiding work.  If he has figured out that he only needs to stand close to his trainer to be allowed to just hang out, then he's got her number, and she needs to be forceful in driving him away--not cruel or abusive, just firm.  

But I'd like to add two points for consideration.

I  suggest starting without a longe line simply because, as a novice, if he does come in or do something like suddenly reverse direction to avoid moving out, you're likely to get tangled in the line, which will cause you to stop for a minute to regroup.  That pause could be enough to confuse the horse and give him permission to quit and stand on you again.  

Remember to keep your body behind the horse's midline with your visual focus on his hindquarters and the longe whip pointed just behind his hip.  You're body language should suggest that you're "chasing" the horse, not just standing there with him.  If you're a novice at this, you might be getting in front of the horse just enough to put pressure on him in the wrong direction.  Stepping toward his head will stop him, make him come toward you, or cause him to reverse direction, none of which is what you're looking for.

This is a team learning situation where you and the horse are both in training together, so be patient, and reward both him and yourself for any improvement.

This is a common problem for horses that don't understand what you want from them. They are lead around for the first couple years and then we expect them to move away from us when we ask. I have taught many horses to lounge. It is very simple but it takes baby steps. On a very short line, walk around the flank of the horse and shoo him forward, as he steps forward praise him and continue to drive him by shooing and clicking to him. As soon as you find the spot behind him that moves him forward, stay there. Walk behind him. You will find that he wants to spin around to face you. Just stay behind him and drive him forward. He will get tired of spinning and start to move forward away from you. Keep him there doing that for as long as he will do it. When he does turn toward you, start over. It will take many sessions to teach him this. Don't rush it. As he begins to understand you, move more to his side. Stay just behind his center. When you want him to slow or stop, take a step toward his shoulder. This teaches him that your position lets him know how fast he should be moving. Perfect this at a walk then move on to the trot, perfect it and then move on to the canter. Be patient. It will not happen over night.

 Thatwindow, that was a super explanation!