Apple issued a support message for Apple MacBook Pro regarding potential distorted video issues related to faulty NVIDIA graphics chips.
Apparently NVIDIA told Apple in Summer that MacBook Pro notebooks are not affected by the faulty chips the informed about. Apple's investigation shows now that there are some MacBook Pro notebooks out there that have issues stemming from faulty GeForce 8600M GT graphics processors.
If you see distorted or scrambled video on the computer screen or no video on the screen than you should bring your MacBook Pro to the Apple store for evaluation. Apple will repair your MacBook Pro for free if it has these issues.
More details in this Apple Support message. Via CNET.
http://www.i4u.com/article20817.html