There is a Microsoft Fix-It which will perform an automated reset of your Windows Update configuration.
This succeeded for me where all other tricks had failed. Including running the Windows Update Readiness Tool, running sfc /scannow
and clearing the software distribution folder.
Look for Microsoft Fix It 50202 in your favourite search engine.
Try running it without the Aggressive option first. Although for me, the problem was only solved after I did use the Aggressive option.