From old hardware to loose cables. Too little detail to start but in short, something of a recurring issue with PCs.
Bob
For some reason, and this is the second time in a week, this has happened, my F: drive has disappeared on my desktop. So I put DVD in and nothing happens.My "devices and drives" only shows my C: drive and my Cloud photos. Frustrating doesn't being to describe what I'm feeling. Anybody help?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic