Which came first, Mario or Windows?

Mario came first, by 4 years. Mario debuted as "Jumpman" in the arcade game Donkey Kong.

Side by side

Mario

Mario first appeared in Donkey Kong in 1981, credited as Jumpman, four years before Super Mario Bros. of 1985 made him a household name. He wears a cap because animating hair at that resolution was impossible, and dungarees because they made his arm movements legible against his body — the design is entirely a consequence of an 16×16 pixel sprite.

Windows

Windows 1.0 shipped in November 1985, twenty-two months after the Macintosh, and it was not an operating system — it was a graphical shell running on top of MS-DOS, and remained so until Windows NT in 1993 and the consumer transition with Windows XP in 2001. Version 1.0 could not even overlap windows: they tiled, because Apple's legal position on overlapping windows was unresolved.