How can we deal with middle school meltdowns?

February 29 |
@offbeatfamilies runs these advice questions as an opportunity for our readers to share personal experiences and anecdotes. Readers are responsible for doing their own research before following any advice given here... or anywhere else on the web, for that matter.
Photo by joo0ey, used under Creative Commons license.
My oldest child, 12 years old, is in his first year of middle school. Without warning, we have hit an academic brick wall. My once mostly straight-A student is now failing half his classes. He's bombing tests and not turning in work.

While I have done my absolute best to keep in contact with his teachers and have talked with him repeatedly about the importance of good grades and writing things down, I feel like I have led my little horse to water but he's refusing to drink.

I'm so tired of yelling and fighting with him; of repeating myself and having to be mean to get him to do anything. I've taken away video games and computers but it still seems like this entitlement is growing and the attitude is growing with it. What do I do? What worked with your children? — Mrs. Daniels