Hi Fiery,
You are spot on.
I deleted the registry path and checked for a .INI file (didn't have one) - made no difference.
I then realised that I had changed my primary display recently (in a multi-monitor set up) so I set everything back to as it was. The Aida 64 window then came up on a secondary display. I then dragged the window onto the 'old' primary display. I then set the primary display back to how I now want it to be. The next invocation then started up fine.
Many thanks- excellent support
Kind regds, JR