I have a late 2007 MBP (15", 2.2ghz, 120gb hd)...I did search the forums but only found flickering screens with the new unibodies.... and it seems to have a grapics card issue, but i'm not positive. Well I'm out of applecare and im afraid of a 500+ genius bar bill. Here are my symptoms: Sometimes when I startup the machine from cold or warm boot, the screen will either come in halfway grey and the top half is the only usable part, or sometimes it will have light faint grey lines throughout the screen and will jump and flicker on and off. Sometimes worse and sometimes less. Sometimes it won't even do it at all. I would say probably about 1/10 boots it will do this. Now, I just put in 4gb of ram from crucial in it about 2 months ago and this problem has been happening for about 1 month now, could it be this, if not, Anybody have any ideas?!