I have a cq50 with windows 7 64bit i tried to upgrade to 8gb and it wouldn't start at all the bios doesnt seem to recognize it so i then tried it with 6gb and it starts but now it freezes constantly i should mention i also upgraded my motherboard and the chipset i have can handle up to 8gb yours may not look here this is my chipset http://ark.intel.com/products/35135/Intel-82PM45-Memory-Controller-Hub?wapkw=mobile+intel+pm45+express+chipset
yours maybe the same or one of these two http://ark.intel.com/products/35134/Intel-82GM45-Graphics-and-Memory-Controller-Hub?wapkw=mobile+intel+gm45+express+chipset+%28embedded%29
I would say it is most likely yo have this one but i am not sure http://ark.intel.com/products/35501/Intel-82GL40-Graphics-and-Memory-Controller-Hub?q=gl40
If you have the gl40 you should take notice that the maximum supported memory for it is 4gb