Windows didn't start out as an OS. It started out as a windowing system for DOS.
That's the landscape all the trademark suits happened in.
Footnote: Windows 95/98/ME was still DOS + Windows bundled in one box. Windows XP was the first consumer operating system derived from Windows NT (which was in fact a proper operating system in its own right). Even Windows NT was trademark-iffy. It was a play on VMS (get it? If not, increment each letter).
That's the landscape all the trademark suits happened in.
Footnote: Windows 95/98/ME was still DOS + Windows bundled in one box. Windows XP was the first consumer operating system derived from Windows NT (which was in fact a proper operating system in its own right). Even Windows NT was trademark-iffy. It was a play on VMS (get it? If not, increment each letter).