I would approach the situation with both a carrot and a stick. First, I'd talk to his math teacher and let her know that I was concerned about his math and taking steps to help him improve his grade. I'd let her know I need more feedback (once a week).

Next, I'd make him earn his computer game time by doing his homework every night. I would have asked the teacher for extra material for nights when there was no homework.

I'd get feedback from the teacher once a week that he was turning in his homework. If he's not turning in homework, no computer games for the next week.

If he is a smart kid, gets appropriate math homework every night and does it correctly, he should pass math.

Once the next test comes back, if he doesn't have at least a B, then I'd ask the teacher for supplemental work for every night. Also, I'd make sure he went over the test thoroughly to make sure he understood what he missed. Math is foundational, and he needs to understand what he did wrong because many sections build on the previous section. If you don't think he is doing this, you may need to sit down with the teacher and your son to make sure he covers this material.

If the teacher gave me feedback that he is not paying attention in class, talking, sleeping, etc., then if the problem is severe I would let my son know that either he pays attention in class or I come and sit with him during that class. And I would follow up and do it if needed. Don't make a threat you won't keep.

It sounds like part of the problem is general motivation. Does he have enough chores? Is he playing too many computer games? He may need extra curricular activities on his college application, so he may need to do some community service and extra curriculars. He definitely needs to do plenty of chores if he's sitting around playing computer games all day.

Also, if the grades are not good there would be no driver's license until the grades are better (again, only if you're willing to back that up).

Next, the carrot. Can you take him to visit some colleges? Would that motivate him? What can you think of that you could promise that would motivate him? A gym membership? A kayak or skateboard? Make sure to explain to him the connection that kids who go to college, get good grades in a major that is hiring have more money for the fun grownup toys. Make sure to point out that we adults don't get something for nothing - we have to earn our surf boards, snow skis, bikes, etc.

You might have a short-term and long-term reward. Short term, once a week if he's done well with his math and other grades, then go out for pizza or whatever would be fun.

Get him interested in something besides computer games if you can. Get him started on the skills he will need for college. He should be doing his own laundry, cooking some for the family, doing yard work, etc.

Last, but not least, I got this tip when my kids were much younger and it's been a great tip. Make the focus of your praise your son's hard work. If he washes the car, praise him for his effort and hard work. If he makes a good meal, praise him for his effort and hard work. Teach your son the pleasure of working hard for something worthwhile.

Good luck whatever you decide.

Since your boy likes to play computer games, why don't have a try with online learning? We've been using Math program on this site beestar. The questions are all very good and DD finds the questions interesting and challenging and enjoys solving them. Plus, Math is free for all grades.
Lisa

If he is thrilled with computer games, he should be writing them. For that, he'll need skills, math being one.

So this is a few years old and all but since it has resurfaced a couple of things I would like to comment on.

I am really concerned that he will not got into a good college - What is a good college? Statements like this concern me. I will answer this for you, a good college is one that your child can learn and be successful in. I see so many kids who are attending the wrong school because they can get in. Every day I see kids that never really had a chance to succeed, fail in the most disheartening fashion possible because they picked a college because of its reputation instead of their chance of being successful. We all want our kids to be successful and achieve greatness but Harvard is not for everyone.

Taking your son's gaming system away and insisting they play only educational games is a recipe for disaster. Please don't do it. You are just delaying an implosion, and creating an opportunity for conflict. His peers are going to have enough influence on him already, don't give them more by straining your relationship at home. Not to mention the fact that one day you might want him out of your house and what is going to happen then. He needs to learn self discipline, a lot more than he needs to learn anything else, even math.

You might try having him punish himself. Explain to him at some time that if he is not successful in school he will be punished. When he is not successful then ask him to assign himself a punishment that he feels is appropriate. If he is too light on himself then don't take the power away from him simply say I think something a bit more punitive is needed until he comes up with one you agree is fair. If he comes up with something too harsh then accept it with less harsh terms. I went through the same thing with my older son. He sets his punishment too high and I would simply lower it. The first time he got a C on a midterm he offered no computer until his grade was an A. I responded with lets just limit it to two hours per day on school nights. He had his grade back up in no time and there was no resentment there. Furthermore, he has taken ownership of the problem.

Your son is a young man struggling with something many young men today struggle with. Help him grow out of it, don't try to push him through it.

My daughter hated math and didn't understand it very well. I was no help -- I had forgotten most of what I had learned. I hired a tutor -- a college student -- to come twice a week. It worked very well, and was worth the money.