OK, so I have a late 2007 15.4" 2.4GHz Macbook Pro which as of last year is out of AppleCare. Just before my coverage ran out, my MB crashed on me, and upon bootup introduced me to my first KP screen. I dutifully booked my Genius Bar appointment and after a few visits they deduced that it was a problem with the nVidia card and was a known issue (at first they insisted it was software related, but the issue persisted). So anyway, AppleCare or not because it was a known issue they replaced the logic board free of charge and until now all has been A-OK. Until today. I got the same screen again. I unplugged my external display and rebooted and it worked fine, but it's got be a little worried. Should I just forget it happened or is this sort of thing usually a precursor to something more serious? Nothings been changed recently except for a harddrive replacement, but that was months ago. Also as I've opened my machine up (to replace the HDD), will Apple even look at my machine if a repair is necessary somewhere down the line?