Erm... correct me if I'm wrong, but don't P4's support SSE2, and isn't the correct Roman numeral for 4 IV? Also, this type of thing had been done, and the whole MB died before it could even post... the idea was maybe the battery busted under the extreme temp. One more thing, N20 and N2 are completely different, and N2 is Nitrogen... a gas at room temp with a freezing pt. of -218C, and N2O is Nitris Oxide... a gas at room temp with a freezing pt. of -90C, and therefore would have turned everything into a block of ice... also known as laughing gas I think.... I guess the joke's on you.
-SammyBoy