Hello there I have MacBook pro 986 mid 2009, Snow Leopard on it with last updates. about three month ago i changed memory up to 8gb (this is the only i changes in HW) now i have blank black screens sometimes. in prev days i have totally 2-3 blanks, but today i boot mac and after 5-10 mins i see next blank screen. the only reboot helps :-/ in this i load FF, torrent, sys monitor and preferences. no new apps was installed in last 3-6 month. last update was a week ago. extern monitor work perfectly. mouse work. audio works. so - only black (LED lighted) screen and mouse pointer. i tryed to switch between videocards - no effect. no "magic corners" i have.