I would like to build on what I have and upgrade Compaq Presario SR5707C Desktop. I would like to change the mother to ASUS M5A78L-M LX. I know I will need new operating system, memory and power supply but can I use a AMD Athlon X2 7850 Black Edition , GeForce 9500 GT .(I have the CPU, graphics card and a 450w power supply ) I would like to use as much of the my current PC as possible and buy new as I can afford.