Please excuse my late reply, I've been traveling.
I am running the 32bit software on my 64bit Windows 8.1 machine. I don't have the 64bit version as I'm just using the disc that came with Roland Duo-capture EX. I would like the 64bit version.
Audio is set up properly as far as I can tell, but I can't test because of the 'New project' problem.
I am the Administrator for the machine, so the answer is yes.
As for cleaning the registry, I always run CCleaner after uninstalling any program so hopefully that takes care of that?
I shouldn't admit this but, I downloaded a copy of the Producer version from a filesharing site just to check, that loaded new projects with no problem at all. (Crashed a few times, but I don't about that) I uninstalled, ran CCleaner and re-installed my LE version from my disc, and again the 'new project' window fails to open properly.
All I want to do is record my voice for the English lessons I do for my school, this is proving way harder than it should be.