PCs designed for Windows 8 are very difficult to downgrade to Windows 7. Stay with Windows 8 and install the free Classic Shell which makes Windows 8 look and feel like Windows 7. That's what works for almost everyone.
Iusing a Samsung Laptop NP510 that came with W8 but after almost a year I am giving up on it to return to W7
I followed instructions to change BIOS before rebooting, but after rebooting the system doesn't access the disc in the external USB DVD drive.
Am I missing a step ?