Problem activating Photoshop Elements 14

I have a version of Photoshop Elements 14 that I installed years ago on my PC and on a small travel notebook. Photoshop Elements 14 was always listed in my Adobe account alongside other software, but now it has disappeared.
A little over a year ago, I switched from my old PC to a powerful notebook. I decommissioned my previous PC and no longer have it. 
Now I want to start working with Photoshop Elements again on my new notebook. When I open the programme, I get the message: ‘The serial number is already being used by the maximum number of computers allowed. You must deactivate another computer...’
However, since I no longer have my previous PC and Photoshop Elements has disappeared from my Adobe account, I cannot deactivate the programme on my previous PC.
So today I called Adobe's telephone support and asked for a solution. The employee was helpless and did not know how to solve my Photoshop Elements problem. He even said that the serial number of my licence was linked to a different name. The consultant finally referred me to this forum, saying that there were very knowledgeable users there who would certainly be able to help :-)
This is very irritating. Does Adobe assign serial numbers for a product to different users?

Does anyone have a solution for how I can reactivate my serial number for Photoshop Elements?