OK I think I've resolved this on my own. A pleasant reminder that windows is just a fancy front end for DOS.
Opened a command prompt window, and ran the following:
Net user administrator /active...

Have managed to setup a user (not admin) account using netplwiz at command prompt. Still can't find any way to correct the existing admin account or add another one.:(

Hope someone can help me out. After 6 hours online with MS support, I am left with a computer I can not log on to. Long story, but as a result of their tinkering I was forced to do a Windows reset....