A few years ago, I bought and installed Photoshop CS6 Extended. I do not believe I supplied an e-mail address at point of purchase. The software worked just fine for years.
Then, the motherboard of the computer it was installed on fried. The hard disk and everything else was OK, but the motherboard had to be replaced to un-brick the machine.
After the fix, starting up Photoshop produced a dialog requiring the creation of a new Adobe ID and put Photoshop into a 30-day trial mode. Apparently, it does not recognize the machine as being the same, though it's running off the same hard drive as before with the same software configuration, and the same screen, machine, etc.. I still have the fried motherboard, if that helps.
In this dialog, there's a "Buy Now" button that does not actually provide the opportunity to buy that product - I could buy a subscription to Adobe Creative Cloud at $240/year and not be able to work offline, but I can't seem to get back the same product I had. I also don't have the original documentation any more; the software had been working for years before this happened.
Is there a way to get the software to recognize the same license it previously recognized?