I'm very new to computers and my sister recently gave me her old computer that had only 2gb ram. We decided to upgrade to 8gb, but when we replace it, the computer came on perfectly fine but the monitor didn't. I have and AM3 DDR3 1666+ motherboard. And the ram i using is two "Crucial Ballistix Tactical" ram. I'm not exactly sure if its our ram because we did screening on the Crucial website to see which ram to get and they said the ram we bought is compatible. Also we tried putting back the old ram and it still did the same thing...