I seem to be having the worst luck with my mac....I bought it 3 months ago, and for the first month every thing was great. Then I started having these random shutdowns; this is with stock ram. So I thought ok, I'll send it in...they replaced the logic board and some cabling. Ok, get it back...turn it on, it freezes after boot up. Awesome. Turn it on again, works fine for a couple days, then freezes some more. Ok, I send it back again. They replace the ram and reinstall the OS. Get it back yesterday...screen starts flickering and showing these weird horizontal lines!!!!! Two repairs and worse each time! I call the product "specialist" and raise hell, demanding a new computer (in a tactful, logical way)...he says he can't do that and recommends I take it to an apple store (90 miles away) to get it looked at. I will go there tomorrow if work permits. At this point I just want a new computer...I don't want to send it for repair a third time where it *may* be fixed...in a week. I literally cancelled a gig (I'm a musician) because I didn't have Logic 7 to use, and this is the only computer I have. How do I convice these guys just to replace my computer?!?! Help!