I worked on an IT helpdesk at an insurance company for the summer in 1996. I had to support IBM PS/2 PCs that would tri-boot Windows 3.1, OS/2 Warp, and Dos. No one operating system had all of what they needed.

Funny side story:

They had a token ring network, and in the network room, there weren't enough physical network ports for all of the employees. Every morning someone would call the helpdesk to say their computer was couldn't access the network, I'd look at the N network cables, find one that without lights to indicate that cable was in use, unplug the inactive one, and plug in the cable of the person w/o access. It turned out on most days enough people called in sick or were on vacation that we could get everyone who needed a connection wired up :)