WHY does my MacBook Pro 17 keep dropping wireless and hardfreezing?

This problem has been ongoing for 4 months or so and I have made 4 trips to the Apple store with no solid answer as to what is wrong with my computer.

The problem began with my computer hard freezing and the only way to get it to restart was to unplug it and pull the battery out. Then it started telling me there was not wireless card installed. It either freezes or drops the wireless, BUT I have discovered that if it drops the wireless then it wont hardfreeze.

When the problem first occured four months ago, I did all updates to the computer and put in the startup disc to see if this would fix the problem. Nothing changed.

Took it to the apple store for a checkup. They ran a quick test for free and no problems showed up. Told me to change the RAM. Nothing changed. Then I completely erased the hard drive and started from scratch in an attempt to fix the problem. Nothing changed.

Took it back to the apple store, They ran some tests and told me the logic board and the graphics card needed to be replaced. So they replaced them. Nothing changed.

Took it back angry the next day and argued with them about this not fixing the problem, they ran tests and told me my computer was completely fine.

However 4 months later my computer is still hardfreezing and dropping the wireless. The only solution i have found to the problem is restarting it until it drops the wireless (it will either freeze or drop within typically 30 mins of a restart) then plugging the computer into a cord.

However I am baffled that there does not seem to be an answer out there for this problem and Apple seems to be completely ignoring the problem and refuses to acknowledge its existence.

If anyone has any experience dealing with the solution to this, I would be ecstatic to know how to fix it! THANKS!