No Available Windows

I should have mentioned the simpler and more important things to check first:

If you press F3 (shortcut for Mission Control), on an empty desktop (any working iMac), it will say "no windows available". (mission control has no windows to show (none to choose and slid) and says this in the middle of the desktop, but it does show the top bar of mission control for other desktops)

Therefore make sure your F3 key isn't stuck, MORESO that your keyboard is fully charged (plugged in - or try some usb spare have you one). Check settings for mission control (though they should be perfect if it's new).

I was having the same problem, not only on my laptop but my boyfriends as well. I finally realized its because I was pressing too hard trying to click on the icons. The computer thinks you are doing 3D Touch and the apps don't offer any 3D Touch windows! hope this helps

I'm sure its replacement will be fine.

Don't waste your time. Put it back in the box and return it for a full cash refund. Buy another one.