USB problems? OS or mobo related?

[freeofparanoia]

I have a shuttle an50r with winxp pro installed, and i recently reformatted, and upon reformat, my usb mouse worked, because i hadn't unplugged it. I started plugging in new devices, such as a camera or an mp3 player and neither worked. I unplugged the mouse and that stopped working too when i tried to plug it back in. I tried updating windows, and i reformatted twice already.. any ideas?