I put windows defender on one of my office PCs, and when it started checking for the latest definitions and updates, I got error 0x80070422

OK, its a really old PII system, but it still works well, so I was hoping defender wasn’t limited to only working on PIII hardware and above.

The solution turned out to be a lot simpler: enable windows automatic updates. (control panel -> administrative tools -> services -> automatic updates (set to automatic, then reboot)

I probably shouldn’t disable so many services, but if the services were smart enough to startup only when needed, then you save yourself a lot RAM.