Lenovo B50-10 Laptop: Win 10 to Win 7

[iWoodzy]

I've got a bank of Lenovo B50-10 laptops with Intel Pentium 2.16GHz with 4GB memory. I'm trying to down grade from Windows 10 to Windows 7 Pro with a few problems.

 

When I try do a legacy boot from CD, I get a blue screen Stop A5 error and stays there.

 

There is no option to boot UEFI from DVD. So I tried a USB UEFI boot, that loads Windows, but hangs on the Windows Logo.

 

I've run out of options, any ideas?

[Ertech]

Have you tied to reset/default BIOS setting?