Audition 3.0

I'm afraid you're going to be somewhat out of luck...

Many years ago, the server used to authenticate serial numbers for Audition 3 was turned off, and as a degree of appeasement, a downloadable version was posted with a 'universal' serial number that you could use instead; any original software that anybody had simply wouldn't authenticate, and would only run for a few weeks in trial mode. Earlier this year, Adobe made a decision (for a legal reason that we're not allowed to discuss) that the only versions of virtually all of their software that was to be available was the current version and its -1. Audition 3 certainly didn't fit into this scenario, and the download and its serial number were accordingly removed from the site.

Now, if you can find a download of that version, complete with its serial number, it will run fine. But it's the only version that will. I was told wayback when that the software might indeed be 'discoverable' on the internet but I haven't tried personally, and I'll tell you why; it really doesn't like running on Windows 10, so it's not a lot of use to me.