Ok i have a 15 inch powerbook and i know they are picky with ram. I used OCZ. Is that known to be bad? My problem here is my computer will lock up a lot but I also noticed it is, I think, only or usually while using firefox. Could firefox cause this problem or is it better chances of my ram. I will go a week with no lockups but then ill just get a whole bunch in a row or a day. And also sometimes when i shutdown it will just sit there with the thing, not sure what its called, but it sits there spinning and i have to hold the power button down to shut it off. I assume its my ram but if it isnt it would be great.