Computer won't power on after removing second monitor. PSU or MB issue?

Karpin

Honorable
Dec 16, 2012
15
0
10,520
My second monitor died so I disconnected it after powering down my PC. Now it won't power on. I have a Asus Maximus VI HERO MB which normally lights up when the switch at the back of the PC is flipped, however now only the start and reset buttons light up and the Q-code display is blank. All the buttons are non-responsive and none of the fans start spinning, not even the PSU.

Does this sound like I need a new MB or PSU?