My HP Pavilion G6 1d40nr laptop started overheating and turning off because the fan had stopped working. I found an identical laptop and installed the fan from it. I kept the original heatsink and fan apparatus, just replacing the fan itself. However the fan from the parts laptop isn't working either, indicating that the problem lies elsewhere. I can't figure it out so I am hoping to get some help here. Thanks a lot!
Fan header on motherboard could be faulty, and check the BIOS to make sure you did not set the system to silent or disabled the fan if that is an option. If you are adventurous you can connect the power wires of the fan to a battery and see if it spins to make sure fan is good.