Turning my sad gaming PC into a media server

In 2016, I built my very first gaming PC, armed with a PCPartPicker list and a ton of Reddit research. We had some good times together: Fallout 4, The Witcher 3, Divinity: Original Sin, various Batman games. Then we got a PS4, then a PS5, then a Steam Deck - the final nail in the coffin - and poor Calculon (for that was its name) sat neglected under my desk, a coffee-stained glorified (but not very ergonomic) footrest. Its giant tower was taking up a lot of room under my desk, and it was too shit to play any modern games. When I looked into the logistics of upgrading any of it, it seemed I’d have to completely gut it and start again, and I really didn't have much use for a gaming PC, let alone the desire to spend that much money. Where do old computers go when they’re no use to anyone any more? That’s right, they become media servers. The first job was to downsize so it could sit nicely in the spare room without taking up too much space. I could have left it as-is, and saved several…