Dell OptiPlex Small Form Factor 7010 Owner's Manual page 74

Steps
1. Disconnect the power-supply cables from their connectors on the system board.
2. Unroute the power-supply cables from the routing guides on the chassis.
3. Remove the three screws (M6-32) that secure the power-supply unit to the chassis.
4. Slide and lift the power-supply unit off the chassis.
74 Removing and installing Field Replaceable Units (FRUs)