License Key 'lost' with old Windows 10

I had to download a different Windows 10 into my Parallels  'app' which erased all the programs, softwares, etc. I had downloaded onto it. I have reinstalled Trados without a problem, but the license key is stuck in the old Windows 10. I need to deactivate it so that I can use it on the Windows 10 I now have. How do I do this?