Anyone experienced before? I remember there is a thread discussing this kind of display issue but I didn't found it. Syndrome: running regular applications (e.g. word, iworks, etc) suddenly system freezes up. The screen is blank with different colors, from purple, light blue, dark, yellow, etc. Question: 1. is this OS level issue? or hardware issue like display panel? 2. I book an appointment tomorrow morning. Do I have a chance to replace it with a brand new one? Thanks.