Please see: http://forums.macrumors.com/showthread.php?t=243868 Ok, I have installed the new memory bought from mac (512mb) but now am having problems, the laptop seems to have some sort of 'drag' going on, everything I do shows up a little later than when I did it a few mintutes ago it even went to an extreme of almost crashing it was so slow, it had a kind of 'strobing' effect, I couldn't do anything so restarted and now it's just a bit slow. I followed the instructions very carefully and did not do anything different from what they said. The new dimm is showing on the computer, but whats going on! Also-now my airport card seems to be non-existant!(I guess that means I havent plugged it in properly?) Any suggestions?