Use this guide to replace the fan inside of your Dell Dimension 4600.
Locate the case cover latch on the back of the computer.
Using your index finger, slide and hold the cover latch down.
While holding the latch down, place your other hand flat on the side of the case and firmly shift the side panel to the left until it disengages.
Grab the edge of the panel and slide it away from the case until it is removed.
Locate the fan and its black, red, and white power cable.
Follow the power cable to the motherboard connection and remove it by pressing down on the clip.
Locate the release clip on the side of the fan and hold it down with your thumb.
While holding the release clip down, look on the outside of the case where the fan lies.
Using the four black notches as a reference, slide the fan towards the open side releasing the fan.