Can Not Activate Windows After Hardware Change

I recently upgraded my hardware, which includes a new CPU and motherboard. After a day of using my PC, the "activate windows" message appeared in my corner and when I have attempted to activate windows, I get the message that my digital license or product key is not valid.

Upon selecting "I changed hardware on this device recently," I get this message.

My windows is a retail version and not an OEM version, but I do not have the product key anymore.