How to solve Windows 7 installation freeze?

Hello,
I recently built a desktop with the following setup:

ASRock Z170 Pro4S
intel i7 6700K
Asus GTX 970 4GB
intel 5series 480G SSD (connected to SATA_0)
WD 4TB red (connected to SATA_2)
corsair 4 x 8GB DDR4
some random samsung DVD writer (connected to SATA_1)

The problem occurred when I tried to install windows 7.  I installed it using a real disc.  After loading needed files, windows managed to get past "starting windows" screen, but freezes in the first screen of installation interface where I am supposed to choose the region and keyboard setup. Key board input does not change the interface, and there is no mouse icon showed on the screen (strange :S)

After some research, I found many have reported windows 7 installation freezing at "starting windows" screen (in contrast to me freezing at setup interface) due to lack of hardware drivers, which can be fixed by setting boot from UEFI to legacy BIOS.

I found a similar report within the forum:
http://forum.asrock.com/forum_posts.asp?TID=2081&title=how-to-switch-to-legacy-bios-for-win7-install
tried the solution suggested in the thread. CSM are all set to legacy, no UEFI boot was used, and boot has been set to 1st: "SATA_1:SAMSUNG DVD-ROM" and 2nd: "SATA_0:intel SSD", the problem persists.
tried to disconnect every optional hardware, and keeping only: mother board, CPU, memory, DVD drive, and  SSD, still freezes.
also tried using two different DVD-ROM of windows 7, no fix. tried using some old-fashioned keyboard and mouse, still seeing the problem.

All above mentioned hardware should contain whatever software that come from the manufacturer.
Could anybody speculate what's going wrong here? Any suggestion to fix the problem is appreciated.

Thank you very much

wardog is correct, of course.

Your problem is a known but curiously not well documented situation in the PC hardware world.

Or I should say it is not well documented by the two most involved in this situation, Intel and Microsoft.

Intel takes at least 90% of the blame for this. Some might say it is 100% Intel's fault.

The Intel 100 series chipset boards, and a few of their SoC processor boards, only use USB 3.0 drivers for all the USB ports, USB 2.0 and USB 3.0. Intel and only Intel caused that to happen (sorry Intel, but facts are facts. If I'm wrong about this, please enlighten me.) Why Intel did this, I don't know.

That works for all the USB ports, but if the OS you are installing does not have a USB 3.0 driver built into it, a USB keyboard, mouse, and USB installation media will not work on these boards. The Windows 7 installation files do not include a USB 3.0 driver.

That also explains why I had problems installing Windows 7 on my Z97 Extreme6 mother board, that has only USB 3.0 ports on the board's IO panel. I had to use a PS2 keyboard, and PS2 to USB adapter on a USB mouse, to install Windows 7.

Intel seems to claim that this only affects the USB 3.0 ports, but users of these boards report the USB 2.0 ports also don't work.

https://downloadmirror.intel.com/25476/eng/win7-usb3.0-creator-readme-v3.pdf

All mother board manufactures also have their own versions of tools to add a USB 3.0 driver to Windows 7. Why (once again) the mother board manufactures become the ones mainly responsible for providing a fix for this, is not fair IMO.

Windows of every version has many native, built in drivers, which it requires in order to work with the many types of existing PC and semi-professional hardware used with Windows. Not including a USB 3.0 driver (or two) seems strange IMO. There may be an underlying technical reason for this, but you would think at least one USB 3.0 driver could be included.

IMO, that seems even more strange when Windows 7 (and Win 10) includes the SiS (Silicon Integrated Systems) SiS RAID and AHCI drivers, dated 10/2008. Ever own a mother board or card with an SiS RAID chip? Not to mention the Nvidia nForce RAID and SATA drivers, for the obsolete Nvidia chipsets, manufactured from 2001 - 2008.

RAID and SATA drivers can be installed during a Windows installation, that option has existed for a long time, Windows 7 has it. So it could be argued that these drivers are not essential parts of an Windows installation, unless the basic driver and INF files are not available to MSoft.

That's why I also somewhat blame Microsoft, even if they did not create this problem.