Last year's NVIDIA GeForce 8600M GT substrate problem is still causing headaches for Apple, who have announced they will be extending warranty support for those MacBook Pro owners affected. The issue, in which overheating of the GPU causes display distortion or failure, can only be addressed by replacing the notebook's logic board.
Warranty details after the cut
In July 2008, NVIDIA publicly acknowledged a higher than normal failure rate for some of their graphics processors due to a packaging defect. At that same time, NVIDIA assured Apple that Mac computers with these graphics processors were not affected. However, after an Apple-led investigation, Apple has determined that some MacBook Pro computers with the NVIDIA GeForce 8600M GT graphics processor may be affected. If the NVIDIA graphics processor in your MacBook Pro has failed, or fails within three years of the original date of purchase, a repair will be done free of charge, even if your MacBook Pro is out of warranty.
The warranty for the GeForce 8600M GT in the affected machines is now extended to three years from the original date of purchase, even if the overall warranty for the MacBook has expired. It's worth noting that the terms of the extension only cover the GPU, not other components.
A list of the potentially affected MacBook Pro notebooks is below. The company is also refunding those customers who have paid themselves to have the logic board replaced; to seek compensation, or report a graphics failure, Apple suggest contacting your nearest Apple Retail Store or Apple Authorized Service Provider.
Potentially affected machines:
[via The Apple Blog]