Just thought I would pass on this bit of info.
My old Dell Inspiron lap top had started to get hot a lot quicker than in the past, noticeable by the constant noise of the fan. Now being a bit worried about opening up the laptop I took a chance and removed the Key board which gave me access to the fan where I could see quite an accumulation of dust and fluff. so being very careful again gave it good vacuum clean. What a difference it makes, the fan only seems to come on occasionally now or when playing video just like new.