"Upgrading"
When XP came out it was quickly discovered that to upgrade from 98SE you had to reformat your drive, reinstall 98, make sure all the WinUpdtaes had been downloaded and installed. Your BIOS had been updated and a few dozen other things.
Then, if you were real lucky, had a couple of days to sit right in front of your monitor nursing the installation along.
You might, just might get the upgrade to take.