Why the heck did he use thermal glue on the <i>fan</i>, is what I have to say It goes on the heatsink to make contact with the CPU holder thingy, since it's the heatsink that's dissipating the heat, not the fan. The fan only needs to be held in place with screws so it can circulate air.

If he'd done it correctly, it'd be a matter of unscrewing the fan, unplugging it from the motherboard, plug a new fan in, and screw the new one on