Looks like artifacts, but programs says different

[iBlackSunday]

So I have had my rig for about 4 months now (Somebody in here built it, it works AMAZING) and just recently, after hooking it up to my parents 55 inch plasma screen, I have been getting blue flicker, kind of like a white noise static every once in awhile. I ran Evga OC Scanner to check for artifacts, but it doesn't show me anything is wrong.

Now mind you, I usually us a 20 inch LCD monitor for normal use, and saw it happen a few times on that screen, but I fixed it by just unplugging the GPU cord and making sure it was in properly.

I am trying to figure out whats going on, because something in my case is making a strange noise, and I have a feeling it's the fan on the graphics card, but it's not loud or something I am seriously worried about.

NOTE: NONE of this is overclocked, everything is running at default.
Set-up:
x1 Evga GTX 560 Ti using the HDMI to Mini-HDMI
ASRock Gen2 Extreme2 Motherboard
Cool Master GX650W ATX12V Power Supply
Corsair Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600
Intel i5 2500k Sandy Bridge 3.3GHz
Hard drive from a different past computer

Let me know what you guys think is going on, and if you have any questions, PLEASE ask. I wanna figure out whats going on here.

EDIT: I am also never able to reproduce it. It happens at random and usually not that oftem, but when it does, it scares the shit outta me.