Dell Vostro 420 (Late 2008) - Manual (Page 123)

System Board
123
b Install the processor onto the system board (see "Replacing the
Processor" on page 126).
a Install the processor heat sink/fan assembly (see "Replacing the
Processor Heat Sink/Fan Assembly" on page 101).
5 Connect the power supply cables to the system board (see "System Board
Components" on page 40 for connector locations).
6 Connect all front panel cables to the system board (see "System Board
Components" on page 40 for connector locations).
7 Connect all the data cables from the drives to the system board (see
"System Board Components" on page 40 for connector locations).
8 Connect any additional cables to the system board as required.
9 Install all expansion cards (see "Installing a PCI or PCI Express Card" on
page 60).
10 Slide the optical drive back fully into the drive bay.
11 Check all cable connections throughout the computer chassis to ensure
that they are secure. See "System Board Components" on page 40 to help
identify connectors on the system board.
12 Follow the procedure in "After Working on Your Computer" on page 45.