I believe I asked a similar question to this before, but the circumstances are a bit different. I'm trying to build a new, reasonably fast computer for around $500. I don't need to build it completely from the ground up; I already have a case, a HDD, a PSU, a DVD drive, a copy of Windows, and the necessary PCI cards. I'm not entirely sure if my PSU is up to snuff, though. I'd like to know what kind of PSU you think I'd need for this type of system.
So, basically I need a CPU, motherboard, video card, and memory for somewhere around $500. Of course I'm going to put it together myself. I'd mainly want to use it as a gaming machine, and I'd like it to be able to play high-definition (1080p) video. So, I'm pretty sure that I'd like the video card to be a priority. I'd probably want a GeForce 7900 of some type, but I'm not sure. As for the rest, I really have no idea.
So for that price, and with that type of use in mind, what parts do you think I should get? In particular, I have no clue as to what type of CPU I should get, except that I'd like it to be mid-range, and probably dual-core.