$500 or less, is it possible?

Hi all, I am in need of some help. Been a loooong time since I built a pc, so I am out of the loop. Need of a new pc, but dont have much cash, so I come to you for advice. Thanks!

APPROXIMATE PURCHASE DATE: I can only buy the parts when I have the money, so I will probably string this out over a period of time and look for sales and such on the parts I need.

BUDGET RANGE: $500 or less ....eek!

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Music Recording using Digital Audio Workstation, Gaming (CoD), surfing the internet, making videos, flash animation)

PARTS NOT REQUIRED: keyboard, mouse, monitor, speakers, maybe OS?

PREFERRED WEBSITE(S) FOR PARTS: newegg.com

PARTS PREFERENCES: whatever fits my needs best. (would like to use AMD, but bang for buck is more important now)

OVERCLOCKING: Maybe, wanting comparing prices, I have and wouldnt be against  SLI OR CROSSFIRE: No

MONITOR RESOLUTION: 1024x768, 1280x1024

ADDITIONAL COMMENTS: current pc is at the end of its life (7yrs)! I am poor, but work in IT so really need pc, but cant afford much. Maybe I can get something decent that will last me another 7 yrs with upgrades here n there.

Thanks in advance!