No way around using Premiere Elements 4.0 without the purchased serial number.
So, let us see if we can find the serial number. From what you wrote, you have been using this Premiere Elements 4 copy before
on another computer. So, the product and the serial number "should" be registered at Adobe.
Go to the Adobe web site http://www.adobe.com, sign in, and, in the Search field, type in My Products.
Follow the My Products search until you reach the page with a listing of your products.
When (if) you see Adobe Premiere Elements 4.0 there, click on it. The serial number should be revealed.
Please let us know the outcome.
I tried that, but either I don't remember my email address I originally used to register with Adobe.com, or I don't have access to the email address anymore, so I re-registered, when I didn't get a reset-password email. If I can find out what email I used, I can probably figure out what the password was, even if I don't have access to that email anymore.
Do you know how I could recover a lost "username"? It should be possible, since they ask for a name and birthdate when registering.
Without posting the actual information, in the days when you registered version 4, did you use your email address as your Adobe ID or do you create a non email address for the Adobe ID?
What are you using now to get into the Adobe Premiere Elements Forum - a new Adobe ID and password or the one that you might have used when
first dealing with Premiere Elements 4?