Troll much? Your information is backwards.
It's not normal for a computer to overheat using flash. It's not normal for a computer to overheat, period. Sure, flash isn't optimised and can become a memory/resource hog, which in turn means the computer has to work harder than under idle conditions (not as bad as gaming or multimedia playback), but that doesn't automatically result in overheating.
Extra fans only help if it improves airflow through the heat sink. Fans on top of the graphics card won't help the CPU. Also, for your comment on thermal paste (not pest), if it does not have thermal paste, it won't be able to run Windows for much longer than 10 minutes on idle, flash or otherwise.
YouTube uses both HTML5 and Flash. How do you think iOS works with YouTube?
Also... What does P2P have to do with overheating computers? They cause routers to overheat, not computers. Honestly...