Or, “How WWAHost.exe” makes me cry. 

Haven’t run Tableau Server on an Windows 8.1 machine – I’m a Windows Server guy myself. 

When / if you install to Windows 8.X, you’ll generally find that port 80 is already in use – the evil culprit is generally WWAHost.exe

WWHost is the process that “hosts” all the “Metro” (tile-based apps) that show up on your start screen – you know – the start screen universally loathed by the world. 

Just kill the process with task manager a couple times. It’ll re-spawn and end up grabbing another port once you’ve got Tableau Server up and running on 80.