This is the computer I use specifically for testing software designed for old computers.

Then use an OS the software was designed for in the first place.

Our intentional built-in obsolescence

His Inspiron 5100 was released about 2004. That's a full life. Put it out to pasture.

I had one that old, and it died. My oldest working machine is from '08, and another is from '09, and they are showing their age with hardware errors. I expect them to die any moment. It won't be worth replacing components, even if it turns out to be cheap. And I personally couldn't, for example, replace capacitors on a modern computer without destroying it. They consume more power in a year than they're worth, anyway, so it wouldn't be cost effective, which his bullshit environmental analysis ignores.

At some point the one guy complaining his ancient box doesn't work will be the only one who notices, because he has the only working one.