The hand is referring to VMS, the system DEC developed to run the VAX series. Gates hired Dave Cutler, who led the development of VMS, to lead the development of Windows NT, from which all modern versions of Windows descend. Windows has an inner core, hidden behind the Win32 API, that bears a resemblance to VMS.
Gates beat out Digital Research much earlier. DR, which had developed the CP/M OS for 8080-based systems, was IBM's first choice to develop the first PC's OS. But they were slow in responding, so IBM went with Microsoft instead. MS didn't actually have what they sold to IBM, but they went across town and bought a nice CP/M work-alike, 86-DOS, aka QDOS, for $50K from Seattle Computer Products and turned it into PC/DOS, the original IBM PC operating system. Naturally, MS forgot to tell SCP the real reason they wanted the system.