make sure you follow the instructions very carefully, and read the whole thing:
http://www.arcticsilver.com/arctic_s...structions.htm
#1 not too much compound,
#2 nothing BUT the compound between the heatsink + cpu (meaning no dead skin cells, no touching it with your fingers... put your hand in a plastic bag... also no air bubble, rub with your finger in a plastic bag in circles to fill in gaps)
if it was a pentium 4, then it shouldn't have fried. most pentium 4's are safe at very high temps, meaning its got a sort of "temperature security"
the only way to tell for sure if it fried is to test. try another cpu, and if it still doesn't work, try puttin the cpu in another system.