Call me stupid, but I upgraded two Windows 8.0 boxes with StartisBack installed without first upgrading StartIsBack. The result in both cases was a a black screen, the box was up, but could not display the desktop, presumably because StartIsBack was hosing things. If you have this problem, the solution I found was: 1. Ctrl-Alt_del and run Task Manager 2. Run a CMD window 3. Navigate to the install folder for your favourite browser (C:\Program Files (x86)\Mozilla Firefox for me) 4. Run the browser, go to the StartIsBack website and download the version for Windows 8.1 5. Install the new version