That crappy power supply is the culprit. Never use generic power supplies. You get what you pay for. Brands like Corsair, Antec, XFX, seasonic are reliable companies and have good power supplies.
Cheap power supplies have crappy low quality components inside and lie about the wattage that they can output. Just because it says 500w doesn't mean it can even achieve that number, it most likely can only do half of what it's branded as.