Dell OptiPlex E1 - Manual (Page 33)

System Board Removal (Low-Profile Chassis): Dell™ OptiPlex™ E1 Systems
To remove the system board, follow these steps:
1. Disconnect all cables from their connectors at the back of the computer.
2.
Remove the expansion-card cage .
3. Disconnect all cables from the system board.
4. Remove the screw that secures the system board to the bottom of the chassis.
5. Slide the system board toward the front of the chassis until it stops.
6. Carefully lift the system board out of the chassis (be sure to lift evenly and not twist the system board).
When you reinstall the system board (before you slide the system board back to lock it in position), push down near each slot to engage the grounding clip onto its
corresponding tab. Push evenly on both sides of the system board as you slide it into position (do not twist the system board).
NOTES: If you are replacing the system board, remove all DIMMs, the video-memory upgrade module (if present), the SEPP/heat sink assembly, and
the guide bracket assembly from the old system board and install them on the replacement board. Also, set the jumpers on the new system board so
that they are identical to those on the old board, unless a microprocessor upgrade is being installed.