I have a 2.2GHZ Macbook Pro with the 8600M GT graphics chipset, OS X 10.5.6. Three problems: 1. Random shutdowns, normally after waking from sleep. No crash logs. 2. Random screen freezes. Needs to be rebooted. No crash logs again. 3. Sudden graphics distortion and flickering. Last for about 20 seconds, then kernel panics. The crash logs are short, and short IOKit and NVIDIA drivers to be the problem. These problems don't happen all the time, but they seem to be happening more often recently. Could they be the symptoms of the faulty GPU?