I have an ancient tower that I spec'ed and built around 2001, still running my beta tester free gift copy of Windows XP. It has a dual Pentium III server RAID mobo with multiple hard drives, multiple DVD's (and even an old SCSI bus PD-CD optical), and max DDR2. The original mobo was an Abit that drove me nuts with that "bad cap" problem, finally replaced with a dual-proc SuperMicro industrial strength mobo.
It just hums along, mostly as a data repository and runner of old but still used and useful software that isn't worth porting over to the other Win 7, 8, 10 and Linux boxes.
I minimize it's internet access now. Several hard drives have been replaced over the years, most everything else just glides along.
I do use an 8 port KVM switch to keep most of them all on one main display screen, and another for a second screen. Plus a neat 5 port HDMI switch which feeds one input on my TV HD video from some of the boxes (using DisplayPort and DVI to HDMI adapters in some cases).
I'm going to (one day...) port my WX stuff over to a power frugal, but operationally powerful, very small HP 8300 Elite class USDT form-factor Intel i5/Win10 box (USDT=UltraSmallDeskTop).
I highly recommend these little machines, partly because as a "Business" class machine, HP provides a lot of support and documentation, for a long time. And they're easily upgraded on memory, drives or faster, better processors (you have to study the mobo and Intel proc specs to get a suitable match).
I put a 'wattmeter' on it before and it only draws about 8-20W at 'idle' to ~45W max (IIRC) running like a demon.
I've also set up one of these HP 8300 Elite USDT boxes aboard my sailboat as a central 'ship's nav & everything computer', in a homemade protective enviro 'locker/box' to minimize the salt air, etc. To save a bunch of wasted power I've bypassed the normal 'A/C brick via an inverter' by running it directly off the 12V boat's power bus (w/a 19V stepup DC-DC) on the big house bank. With some WiFi and Bluetooth USB sticks, it hubs everything.
Probably should have gone with something like an Intel NUC or Rasberry Pi, but those HP's are surprisingly inexpensive as "refurbs" on sale from Newegg, for what you get: a reliable, powerful, flexible, maintainable, low power use machine. The bigger HP SFF models are great too, one of those is my main home machine.