Dell Vostro 220 (Late 2008) - Manual (Page 109)

Power Supply
109
Replacing the Power Supply
1 Set the replacement power supply into place.
2 Replace and tighten the screws that secure the power supply to the back of
the computer chassis.
CAUTION:
Failure to replace and tighten all screws may cause electrical shock
as these screws are a key part of the grounding system.
NOTICE:
Route the DC power cables as you insert them into the routing clips (if
present). The cables must be properly routed to prevent the cables from being
damaged.
3 Reconnect the DC power cables to the system board and drives.
NOTE:
Double-check all cable connections to ensure that they are secure.
4 For the Vostro 220s: