You mean this one? [1] The shells in 3.0/3.1 and NT 3.1/3.5 were identical. Except the latter wouldn't hard crash the machine every time a program did something naughty, which might indeed be confusing to a consumer 3.1 user...

[1] https://en.wikipedia.org/wiki/Windows_NT_3.1#/media/File:Win...