So, I'm not seeing anything wrong with the picture so I'm thinking it's a hardware problem. Being that this is custom built from a mom and pops shop it could be any number of things though. I've seen this problem with custom computers when there is a problem with the power supply. 600W should be more than enough for your system if thats what it's actually putting out. Then again, it could be some thing as simple as a lose connection to your GPU.