Dell OptiPlex 990 (Early 2011) - Manual (Page 30)

Installing The Processor
1. Insert the processor into the processor socket. Ensure the processor is
properly seated.
2. Lower the processor cover.
3. Press the release lever down and then move it inward to secure it with the
retention hook.
4. Install the heat sink .
5. Install the drive cage .
6. Install the front bezel .
7. Install the cover .
8. Follow the procedures in After Working Inside Your Computer .
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