A number of owners of the 2007 and 2008 MacBook Pro systems found that there were some graphics problems that showed either scrambled video output or sometimes black screens. Many people suspected this was because of faulty graphics processors, and had to get their systems serviced to fix the problem.
Recently a settlement was achieved in a class-action lawsuit against Nvidia over faults in the GeForce 8600M graphics processors included in a variety of notebook models primarily from Dell and HP, but also in Apple's 15- and 17-inch MacBook Pro systems.
People who have MacBook Pro systems manufactured between 2007 and 2008 and who are experiencing video problems (black or scrambled output) will be eligible to have their systems fixed for free. Reimbursements will be paid to people who have had these problems fixed at their own expense.
If you feel you are entitled to the benefits of this settlement, you can register to have your system fixed at the Nvidia GPU Litigation Web site. The site has a specific model check section where you can see if your computer is eligible for repairs.