Software that feels like I'm using an old computer?

What would you call that? An emulator? Anyway, I prefer the look and feel of older, less streamlined computers. Give me a Macintosh I over a Macmini anyday (except for the constant switching of disks...that part was annoying... :I). Still, I like older windows, older macintosh, I once used a really hard to find xerox(I think?) computer once that was something like Windows. Know any programs that would feel like using one of those? Heads up, I despise MS DOS. Don't know why, I just can't stand it. So Windows 1.0 or something would be nice. Thanks!