Microsoft allows you to install Windows 10 or 11 without a product key. When asked for one during installation, you can simply skip entering it by clicking the "I don't have a product key" option ...

Learn how to use SLMGR or Software Licensing Management Tool to Install, Uninstall, Activate, View, Extend Windows License.

Windows 10 can be installed with or without a CD or DVD drive. Here's how to do it. Windows 10 software can be installed using a USB since not all modern computers have a CD or a DVD drive.

I used the product key from my boxed retail copy of Windows 8.1 Pro to activate a Windows 11 Pro install done with a MCT-created flash drive. No issues at all.

On startup it didn't see the windows install, or Win boot loader, so I had to nuke and pave the drive. On intsall, I didn't enter the Win 7 Key, and thought I could do it later in settings.

Can't find Windows 10 product key on your computer? Here are three easy ways to find your Windows 10 product key.