Vista cost the school where I work a ton of money.
The computers we used worked great for internet research, office 2003 (documents and spreadsheets), learning games, and keyboarding teaching software. They had small hard drives, but anything we saved would go on our server. When Vista came out, the windows updates were so large that they filled our hard drives and made most of our computers un-usable.
That’s because you put Vista on an old machine. You can’t buy a hard drive that small anymore and it’s been several years since 20 gig was the norm.
Perhaps the drives were partioned with a small systems partition.