Hi guys,
If you go to Settings,
then System,
then Storage, then click This PC (C),
look for 'Other' - click and see a folder called C:\Windows10Upgrade (which is 20.6 MB in my case)
Click on that folder - the Windows10Upgrade folder opens - have a look at it - it's got an exe file, called Enable-WiFi-Tracing!! What the hell is that? Tracing? WiFi? Is that the reason why we just cannot get rid of the Windows 10 Upgrade Assistant? Microsoft's got some explaining to do!