Will the following computer stuff work?

Ok you will want to look on the mobo website for their qualified vendors list or QVL it may be in the mobo manual and check to make sure that the ram is listed. ASUS is a great mobo but their website is difficult to navigate. Power supply should be enough but if you want to get an idea add the watts required by your CPU and GPU. That will get you a rough estimate and you need more than the number you come up with. Also check to make sure the power supply has a 6 pin GPU power rail for the GPU card as it requires its own power supply. You may want to go with a 64-bit operating system to utilize all of your RAM. Everything else looks good from what I can tell. Good Luck!! (I would stick with the dual core as it is a faster cpu 3.16GHz right now vs 2.83GHz. Quad cores are not utilized as of yet so really you just downgraded a bit)