There is not enough info to work with. I have two comps on which the CPU fan doesn't come on at boot. Simply go into the Bios and change the settings. In my case I chose to set the CPu fan to ignore.
You need to tell the Forum the make/model of comp and the type of HSF you are using.
A forum community dedicated to tech experts and enthusiasts. Come join the discussion about articles, computer security, Mac, Microsoft, Linux, hardware, networking, gaming, reviews, accessories, and more!