Have you installed any tools or utilities to replace the start button/menu that could've hijacked that area?
Nope. On the laptop I'm on right now, I just did a fresh install of the 8.1 Pro .iso yesterday after they made it available on MSDN.
I ran into this once -- turned out the folder containing these commands was missing. Check yours:
Make sure you have content there and compare it to a new user (you may have to make one). If yours is empty, copy from the new user.
Weird! My domain account user folder does not even contain a \WinX subfolder. It does exist on my local account, though. Is this a bug? Or is some weird domain policy preventing it? I'll try creating a new domain profile to see what happens on that one.
are you able to right click elsewhere on the taskbar? can you access the taskbar properties?
Yes, right-clicking elsewhere on the Taskbar brings up the normal menus.