Dell OptiPlex 790 (Early 2011) - Manual (Page 52)

9. Tilt the system board to 45–degrees, and then lift the system board out of
the computer.
Installing the System Board
1. Align the system board to the port connectors on the back of the chassis
and place the system board in the chassis.
2. Tighten the screws securing the system board to the chassis.
3. Connect the cables to the system board.
4. Install the heatsink and processor .
5. Install the expansion card .
6. Install the front bezel .
7. Install the cover .
8. Follow the procedures in After Working Inside Your Computer .
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