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You might have a GPU problem. If you just got your Mac, bring it to the Apple Store and get it fixed.
 
bad video card. Try software update if you don't already have the Snow Leopard Graphics Update. Otherwise, march straight into the Apple Store or call Apple if there isn't one nearby.
 
...call Apple if there isn't one nearby.

Just so you know, Apple pays for all of the overnight priority shipping. (They even send you a box and instructions on how to pack your Mac.) I had to get things worked on my old MacBook before it was replaced and they were extremely helpful.
 
Thank you so much. There's one I can go to nearby. I'll probably still call to schedule an appointment.
 
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