Hello... As some of you may recall, I bought the 17" SR MBP in the summer of 2007. About five months ago, nothing showed up on my screen even I rebooted. Connecting to an external monitor did not help. Apple replaced a new motherboard for me because of the infamous Nvidia graphics chip. Things worked fine most of the time except that the screen suddenly turned gray/blue three times. (It is hard to explain. Let's say it is like somebody suddenly put a sunglass with gray/blue coating on you while you are watching the screen. It gives you a feeling of horror. I actually felt vampire were approaching me from behind!) However, the computer returned to normal in less than a minute each time this happened. About 15 minutes ago, this happens again and the screen still has not returned to normal yet. Anybody has similar problem?