Installing

Hi Gee1

What OS system do you have e.g. W10 or MacOS 10.15, 10.14?

If you have a Mac laptop running Catalina then the 32bit installers make it impossible to setup. Otherwise as Dean says, you are entitled to two activations.

If you have an Adobe Creative Cloud account, you can install it on 2 computers and don't need the serial number as it is stored in your online account.

I had Adobe CC installed on 2 computers. I had both die in a short time of each other. When I installed CC on a new computer, I got a message that it was already linked to 2 other devices and was given the option to remove the links to those. So, was very easy to activate the license for a new computer.

What version of Photoshop do you have? If it is an older one (pre-CC) that was not registered, your details may not be in your Adobe account.  If you log into your account, go to My products page (https://account.adobe.com/products), you will see your products and serial numbers (that are registered of course).