Last January, I did a clean re-install of Win 7 Pro on my Lenovo Thinkcentre PC. A few months later, the "Windows not genuine error message" started appearing. I purchased my pc brand new (Amazon seller) 5 1/2 years ago. There is no COA sticker on the pc or the power box. My pc works fine and has my icons, but the desktop is black and the error message continues to appear. I used Show Key Plus and learned my pc was originally a Win 8.1 and the key will not work on Win 7 Pro. On another forum, 7OEMinstaller (https://www.raymond.cc/blog/backup-and-restore-vista-oem-activation-license/ , " Raymond.cc’s Windows 7 OEM License Installer ") was suggested. However, during the install, BitDefender listed it as a trojan and deleted it. I also deleted the download. Is there another way to retrieve the Win 7 Pro key that was used for my pc when I bought it?