Display turns off automatically?

[black.hat]

I gotta problem with my new setup, everything was working smoothly, but , recently i connected my other displays into pc, the middle display turns on as soon as i turn on the pc but in middle way of boot process i hear a switch sound from my motherboard and then the display just turn off. note that the keyboard lights turns off and on once at same time.

I am using dual gtx 690. my displays are BenQ xl2420ts