In December 2016 I was working on getting AppLocker setup for W10 machines; as part of the trial I had connected a W10 1607 machine to the domain, installed a bunch of software and tested what locking down the system looked like - however the system was never actually ever locked down, I just used the event logs to see what would happen.

In January 2017 with my frustrations growing with W10 1607 I canceled all testing I had to wait for Creators Update.

Today I plugged in the system, powered it on and when it got the screen with the time/date (background image), I pressed the control key to bring up the logon prompt and waited.
System hard drive work up and thought about something, before the screen went back to date/time. Again I pressed the control key and waited while the system thought about things before going back to the date/time screen. Again I repeated ... and repeated 

Eventually I created a W10 1607 bootable ISO image, and tried to repair the system
There was nothing to repair, and so I restored system from system restore. It said it was doing something and on reboot I again pressed the control key and waited for the logon prompt before it went back to the date/time screen. 

Again I tried another system restore, this time using an earlier restore point - again with no success. 

In the two hours that the system has been up, it has managed to check into our WSUS server and knows it needs updates .. but I can't get onto the logon screen

Anyone know of any tricks I can try before I give up and wipe it and start again?