Dell OptiPlex 990 (Early 2011) - Manual (Page 19)

Memory
6
Removing the Memory
1. Follow the procedures in Before Working Inside Your Computer .
2. Remove the cover .
3. Remove the front bezel .
4. Remove the drive cage .
5. Press out on the release tabs located on each side of the memory module.
6. Lift the memory module out of the connector on the system board and
remove it.
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