If you're trying to start from scratch, boot to the USB drive, select custom install, delete all partitions until you have a completely unallocated drive, then install W10 to it.
I use option 2 here, http://www.eightforums.com/tutorials...e-windows.html to create my install thumb drives. Works for Windows 7, 8/8.1, and 10. It also works with legacy and UEFI.
On my laptop I get two entries for that one thumb drive, "UEFI Kingston Datatraveller" and just "Kingston Datatraveller". If I select the UEFI entry I get a UEFI install, select the other one and I get a legacy install. I don't ever turn secure boot off. You only have to do that if your installing Windows 7 or some other OS like Linux.
Did another fresh install, this time the UEFI one.
So far, everything looks good.
I'm gonna check for two more days and if everything keeps smooth I'm gonna mark it as solved.
Nevertheless thanks all you guys for your inputs :-)