Dell OptiPlex 390 (Mid 2011) - Manual (Page 22)

6. Turn over the hard-drive bracket and release the screws that secure the 2.5
inch hard drive to the underside of the bracket.
7. Flex the hard-drive bracket and then remove the two 2.5 inch hard drives
from the bracket.
8. Release the screws that secure the 2.5 inch hard drive to the top of the
hard-drive bracket.
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