In reply to Jon Stewart:
> But all I need is to be able to play video and music (lots of), and do normal internet stuff like shopping and UKC. It's plugged into the TV so the screen ain't an issue. Soundcard's extrernal plugged into a good amp and speakers. I much prefer 2-in-1 (a touchscreen + keyboard).
If that's all you want to do, I'd suggest a £30-ish android 'media box'. Plug it into the TV. Use either the SPDIF o/p from the media box, or the SPDIF o/p from the TV (with audio via HDMI from box to TV), then into SPDIF DAC/Amp. Add USB mouse & keyboard; I have a tiny wireless keyboard, and wired mouse.
That's what I do for most of my low-grade computing. I only boot up the desktop PC to rip CDs and any 'proper work'.
I also have a cheap ViewSonic all-in-one PC (Atom, Win7) in the bedroom for MusicBee/Kodi.
And a Win8.1 tablet for running MusicBee to any of the DLNA renderers in the house (often streaming to the BubbleUPnP renderer running on the Android media box...).
My desktop, ViewSonic & Win8.1 tablet are all secondhand (either rescued from skip, or from 2nd hand shops).