Replace the Upper Fan in the computer tower to prevent overheating and computer damage.
Lay the computer on its side; you will see a blue knob.
Turn this knob 90 deg clockwise.
Slide the panel case forward about 1/2 inch while knob is turned.
Lift panel case off computer.
Remove the large blue cover from the computer. There are no screws or tabs holding it in place.
Remove the power supply that connects the upper fan to the motherboard. The power supply has black, red, green and yellow wires.
Remove the rubber grommets from the base of the fan. A screwdriver or spudger may be useful.
Pull the upper fan out of the computer.