Restore your Mac to the original factory settings:

[Poison]

Unfortunately this also didn't work.

Well.. Unfortunately, that leaves you two options:

1.) Replace the battery, or motherboard.

2.) Replace the laptop itself. Mac's are quite expensive, so I would just replace the insides.

There is also one other issue that I can think of off the top of my head, and there may just be a chip that needs to be re-soldered back into place, from being over-heated.