Never mind, I recovered the Windows Product key via Lazesoft Recovery Suite and then reinstalled Windows 10 by creating a installer from the MS media creation tool.
Hopefully this can help someone else in the future.
I am glad to know that you managed to resolve your problem.
We do have official recommendations in order to upgrade the operating system to Windows 10 in our Compute Sticks.
We invite users interested on doing this to follow the instructions given in the following link: http://www.intel.com/support/motherboards/desktop/stck1a32wfc/sb/CS-035724.htm#recovery_media
It is also important to be aware about the supported operating systems for these units, see: http://www.intel.com/support/motherboards/desktop/sb/CS-035602.htm
Is there a guide for installing Windows 8.1 with Bing if we have already tried to upgrade to Windows 10 and then it corrupted (and hence I am unable to recover Windows 10)?
Yes, we have instructions for that as well.
If you upgrade to Windows 10 and experience problems or the system turns unusable you can reset the Compute Stick back to factory mode. This process will reload the original Windows 8.1 Bing version.
Please refer to “Operating System Recovery” in the following web document: