This does not help you. And don't worry, we believe you if you say that the IDE does not show the port.
My experience is the same as ieee488. I got a freshly installed Win10 Enterprise 64 bit (company) laptop. Installed the 1.8.5 IDE and tested all the boards that I have. FTDI (on a sparkfun redboard) was straight away recognized and windows installed the drivers; 16U2 also worked out-of-the-box as well. CH340 drivers I had to install manually (as usual).
And the Leonardo also worked.
Check your PC for viruses and other crap; the install error that you get might be an indication and that message is why it does not work.