So I'm having the same screen flicker issue that I had 3 months ago (on my C1D Macbook). It's a very intermittent problem that, naturally, won't duplicate when I take it to the Genius Bar. Basically, in March, the screen began to flicker and I took it in and without hesitation they replaced the inverter and something else to rid me of my problem. Well, it's back. So I called Apple Care and asked if it was at all possible for me to use my C1D Macbook as credit to upgrade to one of the LED based Pros, and I would pay the difference. My argument was that the LED based displays will not suffer from the same screen flicker issue that the other laptops do. My answer was "No." Long story short, I wound up going back to the Genius bar at my local store and he blames the screen flicker issue on Azureus. I guess I should have removed it from the computer before paying them a visit, but come on. Does he have any reason to think that? He verified that these are his own opinions, nothing from Apple has been confirmed but that programs of that nature mess with Preferences, more specifically Energy Saver. The result is erratic screen brightness. He says he's seen 5 with the same issue and all 5 used P2P programs and once he enabled a second User or renamed the Preferences folder in Library that the problem went away. In no way did he say that he would deny a repair on the laptop...just said that I might want to try format/reinstall or use another user account for a while to see if it reappears. Anyone have any insight? Obviously hoping to pay the difference on the Macbook Pro was shooting high but is his answer even valid?