You can check if your fan needs replacement by following these steps; 1) open up your computer case 2) remove any screws 3) turn off power 4) unplug 5) take off front panel 6) check whether there are any fans installed 7) if yes replace them 8 ) reinstall front panel 9 ) plug back into power 10 ) turn on power 11 ) wait till fans start working 12 ) if not go ahead with step 13.