These screenshots of RISC OS were taken using Arculator, an Acorn Archimedes emulator. RISC OS was an English operating system developed by Acorn for their ARM powered personal computers. It is currently still being actively developed and there is even a version for the Raspberry Pi!
The RISC OS 3 splash.
The RISC OS desktop. There are no menus, or icons on the main desktop or "Pinboard" as Acorn called it. There is a sort of task bar on the bottom that contains icons for the drives, a link to the applications folder, a color palette thing and the main menu button, all in that order.
I'm not sure which key you would press on a real Archimedes, but for me pressing the Context menu keyboard button opened up what a modern user would consider the right-click menu. This shot shows the Pinboard's menu as well as the about window.
This is what happens when you click on a floppy disk drive without having actually inserted a floppy.
RISC OS includes a few basic applications by default.