My old Dell Latitude E6400 has been working fine recently but now the fan has stopped working. The fan spins for a few seconds at startup and the will not spin any more causing the co.puter to overheat and turn off. I loosend the heatsink on the cpu and I think the computer thought it was overheating because it then ran at a high speed but eventually turned off. I changed ram reseated everything and nothing seems to work. The only problem I can think of is that a sensor has broken that is for the cpu temp. Any help is appreciated.