Please help! third GPU >> MSI Z97 Gaming 5

[XETTAP]

Can anyone please tell me why the GPU isnt work? Here are picture of the Rig.

Supply: http://imgur.com/qgDrH0U
RIG:     http://imgur.com/a/Vv69p

As u can see two GPUs connected to the board x16.
The third card i connect via USB riser to 1x between the two GPUs on Board.

When i turn on the PC on the fan of third GPU do not go on > this http://imgur.com/a/Vv69p
What can be the Problem?

System
Win7 64Bit
MSI Z97 Gaming 5
Intel Celeron 2x2,8GHZ 8Gb
3 ASUS r9 280 3GB
1x be quiet 700W
1x be quiet 550W

USB Riser:https://www.amazon.de/ELEGIANT-Express-Extender-Adapter-Mining/dp/B01HHLQRBK/ref=sr_1_1?ie=UTF8&qid=1482527358&sr=8-1&keywords=usb+riser

I very appreciate every help. Hopefully can find the issue. Thank you in advance

[Set Ready Go]

I suspect it could be a bad riser for that gpu.

im no expert in these matters but when i have had problem with pcie1 ports not working for risers i have went into bios  and changed the settings to 1x or maybe auto will work for u, for the pci port i mean.

so yea try see if it boots up  when u change in bios for the pci e port.

good luck.