All Windows Updates Downloading 0%

Well I reset folder rights to their defaults like the OP with the 3rd party tool mentioned in his last post. It's basically a collection of scripts you can run to fix various issues. At your own risk.
Didn't work for me, but worth a shot. I didn't run the tool in Safe Mode, though, which it made a point of notifying me about. And I only ran 3 select fixes regarding Windows Update. There was a whole bunch, might try to rerun the tool with all Windows Update fixes selected.

Quick update (sadly I couldn't find an edit buttton): After running the Windows Update repair preset in the third-party tool in safe mode (which can handily be started by clicking a button in the tool and restarting), my updates are now downloading and installing. So it was basically the same solution as the OP, except last time I only repaired permissions, which apparently weren't the problem after all.