Before replacing any of the fans, unplug the PC to avoid an electrical shock hazard. Exercise caution as there are sharp edges on a PC and its components. Always wear a static electricity discharge strap when working with your PC's components to avoid damaging your PC.
Unplug the PC.
Disconnect all wires from the back of the PC.
Open the case.
If replacing a floppy drive disconnect the power and interface cables from the drive and remove the retaining screws from either side of the drive.
Identify the position of the #1 pin on the interface connection on the back of the drive.
Choose the location for the floppy drive so that the drive will have a opening in the case's face plate and so that the power and interface cables will reach the drive.
Mount the drive so that he eject button is under (not over) the slot for the floppy.
Connect the interface cable so that the cable's #1 pin matches the drives #1 pin.
Connect the power wire to the drive.
Position the drive and secure with the mounting screws. Always use the screws supplied by the manufacturer. Screws of the wrong size or length can damage the drive.
If it is not already, connect the interface cable to the motherboard's controller labeled "FDD" so that the cable's #1 pin matches the motherboard's #1 pin.
Double check all of your connections.
Replace the cover.
Reconnect the wires removed in step 2.
Plug in the PC.
It may be necessary to configure this drive in the BIOS settings.