Not strictly retro, but worked on a 10-year-old PC for somebody who wanted Windows 10 to replace their aged XP Home install. The PC was a quad core Socket AM2/3 system, with 2GB RAM & basic Radeon 2100 onboard graphics. So first thing I had to do was max out their RAM to 4GB (max supported by motherboard).
They were a bit hesitant to pay for a retail copy of Windows 10 whilst Microsoft are still offering it free to 7 & 8/8.1 users, so I decided to cheat the system for them and stepped through the various upgrades required: XP to Vista to 7 to 10!
It was an interesting experience doing all those upgrades. The upgrade from XP to Vista was excruciatingly slow! The performance of Vista was absolutely abysmal, just like I remember back in the day and this was WITH SP2 slipstreamed in. 🤣
Going from Vista to 7 made the PC liveable once again, so much smoother and Windows 7 ran great.
Finally upgrading to 10 was a fairly smooth process, but as for running the OS - we were back to dreadful performance once again. Just goes to show how terrible Windows 10 really is! Swapping to an SSD solved the Win 10 slowness problems however. An SSD really is the only sane way to use Windows 10.
They only really use this PC for general office usage and light web browsing, so the diabolically crap onboard Graphics suffices, using old drivers.