I am always a bit surprised that this is still asked on a Windows 7 forum. The reason I say this is...what you see with memory usage is one of the primary reasons people use Windows 7 and get the best performance from it. Windows 7 caches your most frequently used programs, so they start up faster. As someone on another forum once said...if you don't want to use your omputer's memory, remove it and put it on your desk. That memory will be freed up in the event you run something intensive, like a game.
As for the heat, that is why, regardless of what marketing departments tell you, laptops aren't really meant for gaming. Towers are designed to handle hot components and allow for much better overall cooling. If you can get an intensive game to run on a laptop, great, but don't be surprised if the laptop heats up quite a bit.