The antec 300 and 900 (on sale for $89 shipped at newegg with promo code- ends today) will both take any standard atx or micro atx motherboard and any atx power supply. The 900 is superior for it's multitude of fans, but the 300 will be adequate. Newegg has a corsair 400w ps for $30 after rebate, last time I checked. It will work fine with your 4650. Don't buy a cheaper ps just because it claims to have a higher wattage. Corsair, antec, ocz, enermax, seasonic, and pc power and cooling don't overate their power supplies at full load. Before moving stuff out, make a diagram, especially of the case connections to the led lights and power switch. The main power supply connections are the same on all power supplies, and the corsair should have the 6 pin pci-e connector if your video card uses it. I just moved all my compaq stuff to a different case recently; It's not hard, but take your time and don't forget to install any hardrive rails if required for cases that use them. And be sure to install the motherboard backplate flush, and remove any extra case standoffs that touch circuitry and don't line up with a hole on the board. You only need to use 4-6 standoffs to mount the motherboard. Standoffs are 1/4 inch brass or silver colored that screw into the case under the board.