If you're not getting any beeps whatsoever, then you're probably looking at something failed, probably motherboard. It could also be CPU. If it were RAM, you'd be getting a beep code and/or a POST at least.
Was everything packaged in anti-static bags or foam? A static discharge could have damaged something.
You're definitely looking at a hardware issue of some sort.
I certainly hope you didn't get burned by the seller...