3. - If there is already an installed mike, remove it.
In case of mikes connected to grooves (Slot A or Slot 1) it will have to liberate the eyes of the wings, which design changes a little from a few basic badges to others and according to the type of cartridge used (none in case of the Celeron for Slot 1 or the adapters of Socket 370 to Slot 1, go nudes); in any case, it is easy. With free them, pull the mike up, and it is already.
If it is a question of a modern mike for socket, the operation is also quite simple thanks to the mechanical system ZIF, who allows to install the mikes without realizing force by no means. The bothersome only thing can be to release the metallic hoop that holds the fan; put attention on having done it, do not be that it comes undone suddenly and infuriates the motherboard, breaking some of the lines of circuit...
As soon as the fan was removed, to release the mike simply put the lever in vertical position, with what the ancient mike will have to remain completely free.