You can use the both of keys, because they comes with the laptop.
And you also can upgrade the RAM to 8GB, but the onboard GPU Intel® 4500MHD is not the good GPU for the CS3 ( I don't use the vegas8).
Ok thanks, I will go ahead and clean install to x64. To be honest I think I would of done it eventually anyway because I'm just that type of person. The reason I want to switch is because I found out my E5400 is the best version you can get of it (excluding of course the XP Pro Downgrade OS). My laptop came with discrete video and not the UMA video option (discrete video is the only reason why the laptop can be upgraded to 8 GB). Discrete video is NVIDIA NB9M and not the Intel 4500MHD so I lucked out!