Monitor blinks when opening video files

I need some advice, I've got a dual monitor setup on a HP DC5800 SFF with a Nvidia NVS Quadro 290 graphics card.

What keeps happening is when I start to play video files, my second monitor will blink or flash black for like 3 seconds. The same applies when I close the player. My default media player is Zoom Player but it also happens with WMP. Although I've tried disabling 'Accelerated Video Output' on VLC and it doesn't happen.

Someone suggested it's an overlay issue, the only decoder I generally use is FFDShow.

I've updated the drivers to the latest version, which hasn't made any difference. Could this indicate I might have a faulty graphics card?