"that Zerox had a windows “CONCEPT” for a digital screen on a copy machine....Not for a personal computer...."
The Xerox Star, the machine that Xerox used to introduce the GUI and from which Apple and Microsoft gained inspiration for their respective operating systems, was a personal computer, not a copy machine.
June 25, 1985: Bill Gates Proposes Mac Licensing in a Memo to Apple
June 25, 1985: Bill Gates Proposes Mac Licensing in a Memo to Apple