Just wanted to follow up. I downloaded an ISO of Win 10 from Microsoft for people in my situation. I removed all other SSD and HDD. I set up the M.2 with Windows 10, and it accepted my Windows 7 key. System boots fine. I added my SSD and HDD. Booted perfectly. However, in the BIOS/UEFI, there is a Windows Managed prefix to the 960. I moved over everything from the SSD's User folder. I am recovering everything from the SSD and I will reformat it.
Anyways, steps in the right direction. I will probably make my SSD a folder for Steam and some other programs.