Compaq Evo D310 MT Hardware Reference Manual page 29

Hardware Upgrades
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2–18
6. If replacing or adding a new expansion card, align the edge of the
expansion card with the slot on the chassis and gently press the
card straight down into the expansion slot.
Replacing or Adding an Expansion Card
When installing an expansion card, press firmly on the card so that
the whole connector seats properly in the expansion card slot.
7. If you have replaced or added a new expansion card, store the old
card in the anti-static packaging that contained your new card.
Hardware Reference Guide