Screen goes black (no signal) when playing games

[strike_yong]

Hi I got my dual monitor setup recently and my monitor keep losing connectivity while playing games like CS:GO or Dota 2. It works fine when I'm not running games. I just newly got my GPU 2 days ago. My main monitor used a DVI to VGA converter(seller told me it's active converter) meanwhile my second monitor used a HDMI to VGA converter(seller told me it's passive converter) to get them connected to the GPU. I tried to unplug my second monitor and just using my main monitor to play and it works fine. Will that because of my PSU or driver problem?

System info:
PC Upgraded from HP Compaq 6000 Pro sff
OS: Win 7 Professional x64
CPU: Intel Core 2 Q8400s
GPU: Gigabyte GT1030 LP
PSU: 240w (not upgradable because it's a proprietary PSU)
RAM: 1x4GB and 3x2GB
HDD: 1x160GB and 1x250GB
Gaming keyboard and mouse plugged in(razer blackwidow chroma and deathadder 1800)

I have tried:
-Updating to the newest nvidia drivers
-Running different games and it happens in them too.
-Unplug my dvd reader to keep my pc with enough power supplying.

I'm planning to build a new pc with higher PSU but before that I wanna solve this first.

Looking forward for your help and support. Thanks!

 

[Calvin7]

Both Gigabyte and MSI list the recommended power supply for the GT 1030 Low Profile card as 300 watts or greater. Since you don't meet the minimum power requirements it is understandable that the card fails to work properly under a load.