Quote Originally Posted by Edwin View Post
Make sure you have your backups in order!
So there was one wrinkle. Only one drive can be marked as "System" and that's where boot is handled regardless. In my case it was the Windows 7 drive. I tried disabling the SATA controller for that drive and sure enough it would not boot the Windows 10 drive. What I had to do was run the REPAIR option off my install disk and choose "ADVANCED" then "AUTOMATIC REPAIR - Fix problems that keep Windows from loading" and viola! It marked the Windows 10 partition as SYSTEM and after reboot it loaded normally.

Then I re-enabled SATA 0 and only then did I delete the old Windows 7 partitions off the old drive and re-partition it with a clean NTFS for data :-)

Now I have a 100% Windows 10 machine :-) Thanks for the help guys!