I had the same problem with the fan on my laptop (this same model) but only after it had been disconnected and removed to service another part. If this is a possibility with your machine, try doing as Oldturkey03 suggests. When you get to the connector for the fan, look inside the plug socket and make sure none of the pins haven't been bent. One pin bent slightly prevents the connector from making contact. This keeps the fan from operating correctly and it's a simple step. I always try the no cost simple things first. Hope this helps.