OK, when you plug the board into the USB cable and then into the PC, does:
1) The PC acknowledge that a USB device was attached? (For Windows XP you get one of those little text bubbles, or it makes a "ding-dong" sound?)
2) Do any LEDs light up on the board? Typically, on most boards you'll get a yellow LED glow for board power and a green or blue LED glow for USB communications.
---Tom