Dell INSPIRON 531S Owner's Manual page 159

3 Align and press the heat sink and fan assembly till both snap in place.
1
2
3
1 fan
4 Replace the heat sink assembly (see step 9 of "Installing the Processor" on
page 150).
5 Replace the cables that were removed from the routing clips on top of the
processor fan assembly.
6 Connect the processor fan cable to the system board (see "System Board
Components" on page 107).
NOTICE:
Ensure that the fan is correctly seated and secure.
7 Replace the computer cover (see "Replacing the Computer Cover" on
page 165).
8 Connect your computer and devices to an electrical outlet, and turn
them on.
2 fan cover
Removing and Installing Parts
3 heat sink
159