Again, thanks for the reply and new suggestions on this. I am very appreciative.
I should have mentioned that I already used CCleaner's registry cleanup tool between installs. However, I did not think to make any attempts to uninstall the ASIO drivers.
I will try this later and report back.
I am accepting that I may just need to re-install Win 7, so am preparing to spend tonight backing up all my video work, software and settings ready for the inevitable
