To reseat a part is to physically extract it from its socket or connector and reinsert it firmly. This action scrapes away microscopic oxidation on the metal contacts and ensures the mechanical latching is fully engaged. It is the most common first-step troubleshooting technique for memory modules, ribbon cables, and expansion cards that are throwing intermittent errors.
Heard on the job
The motherboard isn't posting, so pull the RAM sticks and reseat them before we check the power rails.
Insider tip
Always reseat components before assuming they are dead. A surprising number of hardware failures are just loose connections caused by thermal expansion or shipping vibration.