On this day and age I have successfully activated a Windows XP machine
This is a really old computer that sits as the main controller in a test jig, it uses an ancient PXI card from National Instruments to link with the jig chassis.
The original disk became corrupted or had bad blocks, it wouldn't boot at all, only after running chkdsk on the c: partition.
So I cloned the hdd to an ssd and it booted first try but the happiness lasted a few seconds because it threw me an activation screen saying that a significant part of the hardware had changed and I needed to reactivate it.
Ok, I thought "let's do the phone activation" just like I did last year with a similar machine!
Selected the country and it gave two numbers, one local and one toll-free.. Neither worked...
Instead of panicking I tried for the first time a tool called xp_activate32.exe inside the Windows Sandbox app in a newer win11 machine, as most sites would tell it was a virus.
It got activated just as easily as possible, faster than calling and punching in the numbers from step 3 and hearing back the numbers to type them in step 4.
I decided to make this post just to show this off and share the link I used in a comment below.
Cheers!