Registered Serial Number for Audition

Couple of things: Yes, Audition 3 was pretty comprehensive. Don't agree about RX7 - once you've got into it, it's pretty amazing. But hey, it should be - it's specialised software, and for clean-ups, it has a lot more tools.

You cannot install an original Audition 3 at all, however much you registered it - the validation server was turned off years ago. For a long time there was a version you could download, with a 'universal' serial number, that anybody could use. Recently though, for legal reasons we're not allowed to discuss, that version was removed too. So unless you have access to that version (somebody else's download), I'm afraid you can't install Audition 3 at all. I have to say almost in the same breath that Audition 3 doesn't particularly like running on Windows 10 - many people have run into difficulties with it, of one sort or another. You would be much better served with a later version, which was at least designed to run on a modern OS.

There's an official blog entry about which versions of software will be available in future - basically it says that it will only be the current version, and its -1. Nothing else at all. You can read it here: Changes to CC availability