ASUS Z170-A, red LED near southbridge on and crashing on boot

This is a new build and I have windows 7 freshly installed. There are 3 main issues im having

1. computer would get stuck and display a black screen after showing the ASUS logo and the red "Boot Device" LED below the southbridge would stay lit (normally the LED sequence would be CPU LED > RAM LED > PCIe LED > SB LED > then turn off and enter boot)
2. computer would crash while trying to boot into win 7 and come back with a request to go into windows startup repair. using startup repair would also crash the machine
3. the computer wouldn't recognize USB devices. i know win 7 doesn't have native support for USB 3, but the problem exists even when i plug it into the 2 USB 2.0 ports
4. i cannot flash the BIOS anymore, any version i try to load comes back with the message "selected file is not a proper BIOS"

i searched online and found CSM (compatability support module) could be the problem, but i've tried all 3 modes (auto, enabled, disabled) and yielded similar results

i also tried reinstalling win 7 on the same SSD, thinking it might be a bad install, but the problems continue

is there any way to flash an older BIOS onto the board?

parts:
6700k
ASUS Z170-A
Kingston 2x8 16GB 2133mhz

*the BIOS is updated to the latest version

please help =(

Hello chaos mate I don't know about going back a BIOS version but have you got the RAM sticks in the first to use slots? as some boards use 2&4 for the first two instead of the usual 1&3.

Now I don't know what you have setup in the BIOS as my Asus board in the Ivy Bridge had to have certain settings to run properly or whether you have the drivers for those USB ports installed correctly by that I mean from the Asus site not some other source.

So could you let us know if you have set anything in the BIOS yet??

Ok mate if you have bricked the BIOS / board then you will not be able to get to the BIOS unless I am terribly mistaken. Now my Asus boards use F2 to get into the BIOS while powering up you just tap that key. Now you should end up seeing a screen something like in my pic it might not be exactly the same but very much like it. In there the Advanced settings are for overclocking setting the boot order the ACHI secure boot or not etc etc
There are lots of settings and they do take a bit of getting used to.

Your drivers are here Access Denied now how you get them updated is going to be a problem if the USB's are not working because I usually load them onto a stick and then run them from it - particularly the LAN and WLAN so that you can get onto the net.

Now you say you cannot get a proper BIOS so just where did you get the BIOS from?? it should have been from the link above - anywhere else is not an option - for me at least.

Anyway let us know if you do have the BIOS come up please.
.

Hi,
Yep as far as I've noticed cms would only need to be enabled
Other setting except for uefi should be as Mega... has stated
Using uefi when os type is supposed to be other os seems to me to be a conflict ?

Did you use the asus tool to create the media
Access Denied

Was the hdd or ssd formatted as gpt or normal mbr ?
Hard Drive - GPT or MBR

If the led light is on look through your mother board manual for the error possibilities it applies too.
Flashing bios well that is in it's self a risky thing to do
I've never done that personally a tad too chicken :)

But MS has released some pretty weird updates that do not apply to any version except Ultimate and enterprise that did effect pro and home premium for a feature we can not even use.
https://support.microsoft.com/en-us/kb/3133977

Access Denied

Megahertz07 said:

To install Win 7 on a Z170:
On BIOS
- Set OS to other
- Disable fast boot
- Disable secure boot
- On CSM set boot to UEFI

To have USB support you have to add the drivers to the Win 7 installation disk. To do so, Asus provide a program to do it.
I fond a way to do it: Create a Windows 7 USB flash installation with new drives for new MB's

win 7 is already installed on the SSD, i used a legit disc and a DVD drive. i know win 7 doesnt support USB 3.0 natively. you would only need the USB drivers preloaded if you plan to use USB to install win 7 right?

i disabled fast boot but i cant disable secure boot. it only gives me an option to change the OS type (windows UEFI mode OR other OS). it has been on "other OS" the whole time

for CSM, here are the current settings (in bold)
Launch CSM.......................................(Auto, Enabled, Disabled)
Boot Device Control.............................(UEFI and Legacy OPROM, Legacy OPROM only, UEFI Only)
Boot from Network Devices...................(Ignore, Legacy Only)
Boot from Storage Devices....................(Ignore, Legacy Only, UEFI Driver first)
Boot from PCIe/PCI Expansion Devices....(Legacy Only, UEFI driver first)

Ok mate do as megahertz and TZ have said to set in the BIOS any drivers mate you need to get from the Asus site because unless I am reading it wrong you are relying on Windows to install the drivers.
If you have access to another machine then download those drivers to a stick and just try installing from it it might just be that the ports may work doing it like that anyway that is what I would try.

Now the hard drive is that listed as GPT disk or a plain MBR one??