Win 98! I hope it was atleast Second Edition!
I had a guy come into the shop with an IBM PS1 with a broken floppy disk. There are no ports on this thing and he was still using it for a spreadsheet he started years ago.
I could not even get the data off the HD because it was a whopping 80MB (not a typo! 80MB) with a Single edge pre-IDE connector ( I don't remember the acronym at the moment). No power plugs for either the floppy or the HD. They were powered through the data channel.
At least he did not want to sync his smart phone! LOL