Fitter, reducing heat inside your Hewie is always a good idea, keep the air moving and the fan spinning. The accumulation of dust and cat hair is not very helpful in achieving this goal. You can have a look inside without opening your laptop: the guys of CPUID have several nice, lean and mean tools to do this. To check the temperature of your processor and hard disk try HWMonitor
. In limbo about memory expansion, what type of memory do I need? Another classic: CPU-Z
. A bunch of free Christmas gifts, all year round. Go to the tabs memory and SPD and there you'll see all the details about your memory.