I tried searching in google and on this forum, but I don't really know how to word the problem I am having. This has happened four times in the last week, 3 times today. While working in iPhoto and Lightzone (not Lightroom), my LCD all of a sudden displays bunches of little tiny blocks of color that eventually take over the whole screen. The screen freezes, and I have to shut down by holding down the off button. I just got my MBP home last night from Applecare geniuses and they replaced my hard drive. I was having other issues, and took it in for repair. I suspected a failing hard drive, but they said they were going to run the thorough diagnostic tests. I even mentioned the colored block problem to the Genius, but I really wasn't sure if it was an isolated issue. I didn't make much out of it, because my main problems were speed and spinning beach balls. Does anyone know if this a graphics card problem or an LCD problem? And wouldn't it have shown up on the tests they ran?? I am concerned because I would hope they DID do the tests, and not just replace the hard drive. I should mention that I am not running the MBP w/ 4gb of ram (as my signature states) - I am running on the original 2gb of ram for now. Could it be ram? I just figured I would post here first to get some information before I take it back in. sigh. thanks in advance!