1. Turn off the laptop and unplug it. Remove the battery and hard drive. Remove the screw that holds the cover in place, then pull out the hard drive.
2 Turn the laptop over and remove the screws on the bottom that hold the keyboard in place. then lift the keyboard up and out. Unplug the flexible ribbon cable that connects the keyboard to the motherboard.
3 Remove the screws that hold the keyboard bezel and palm rest in place. Carefully pry loose any plastic snaps on the sides, then lift the bezel and palm rest up and out.
4 Unplug the Acer Aspire 4715Z cooling fan. Remove the screws that hold the heat sink and fan in place, then remove the entire unit from the laptop. Remove any thermal compound residue from the bottom of the heat sink and the CPU.
5 Plug the laptop in and turn it on. After you use it for a few minutes, you should hear the new fan running and feel warm air blowing from the vent on the side of the laptop. A fan does not run continuously, so don't be concerned if the Acer Aspire 4715Z cpu fan shuts off periodically.