Now, you're giving us something to go on. Didn't mean to "rag" on you...but as much information as you can provide will eventually help. Worry 'bout giving too little, Tom's server can handle a little extra banter.
Look in Device Manager and see what it says about the card.
Occurs to me, too, that you should look in XP's Event Viewer. Haven't gotten my XP machine up again, working on it right now, taking a break to see what's here and what others are fighting...for Event Viewer it's in Start/Programs/System Tools I think...if the OS has the focus just hit F1 and help will come up...type Event Viewer in the search and then hit display and it'll tell you how to open it...look to System and Application logs for clues.
Yours may be a USB issue...while you're in Device Manager and Event Viewer be watching for it. In device manager make sure there's no yellow exclamation marks.
I haven't organized this very well, but there are things here to try...and if you get stuck...let us know.
Post back with failure or success.