2Aktion:
Today got the same "not powered" issue from once more customer by email. Later he wrote that they've bought another Kinect, and it works fine. So maybe it is some hardware problem in specific instances of Kinect. It is strange that it is also computer-dependant, as you say your Kinects work fine connected to laptop.
Anyway, your Device Manager screenshot definitely shows that there is some problem between your devices and Kinect SDK drivers. Instead of "Microsoft Kinect Audio Array Control" devices under "Microsoft Kinect" node there are "Kinect USB Audio" devices under "Other devices" node. You can find the "correct" picture in Device Manager on
this page.
Also,
here there is a sequence of connecting Kinect to PC:
1. Connect the power supply for your Kinect to an external power source.
2. Connect the Kinect to a USB port on your PC and wait for Windows to recognize it.
3. All the drivers, including audio, will load seamlessly.
I think, order of steps 1 and 2 can make a difference.