Hi Jocelyn, I had exactly the same problem with this update looping between downloading and installing.
Turning off Norton360 made no difference.
I tried the Windows Update trouble-shooter with no result. It just said it couldn't identify the problem.
I tried to manually reset Windows Update, that wouldn't work at all, as it refused access to the rename the SoftwareDistribution folder entry. Just kept saying 'Access Denied' even though I was running the command prompt as an administrator.
After many. many tries I gave up! Restarted the PC and a very strange thing happened! When the PC restarted it came up with the 'Configuring windows updates' message. However, on checking the update history, nothing had actually been installed. Now every time I restart the PC it says it is 'Configuring windows updates' without installing anything. It's all very weird.