XP before SP2 had USB 2.0 issues. But it's possible some worm or other had done it's damage since hard disks are not protected well enough to rely on for backup. I've written this numerous times here and posts like your continue to show up.
Read http://reviews.cnet.com/5208-7590-0.html?forumID=67&threadID=28919&messageID=328179 about how to scrape files off such drives.
That's not passing the buck. WD didn't write the software.
I have been backing-up my system to a Western Digital External Hard Drive for about 6 months. Recently my desktop computer (Sony Vaio, Windows XP, pentium 4, 1 gig ram) internal hard drive failed - when I tried to boot, I got a message saying "missing operating system". Knowing I had everything backed-up to the external drive, I disconnected it and reformatted the internal hard drive. Now the external drive doesn't show any data on it. It shows a bunch of empty folders. It's an 80 gig drive which was 95% full when all this happened. Now it shows 3 gig used and 77 gig available. When I contacted Western Digital, they told me to contact the backup program company - pass the buck as usual. What could have happened to all the info on this drive and what can I do about it?