I'm not sure about xp but this worked for me in Win 7. My flash drive suddenly started appearing as a disc drive, and my data couldn't be seen or accessed as before. Go to Computer, or My Computer, right click affected flash drive, and hit "Properties" at the bottom of the list that shows up, then click the "Hardware" tab. Click on and highlight the affected drive in the list and then click the "Properties" in the bottom of the window. Go to the "Driver" tab in the following window and click on "Uninstall". This should uninstall the driver that is causing the flash drive to read improperly. Now remove the flash drive and re-insert it. After you do this you should see a notice of new drivers being automatically installed for the flash drive. Now, when you go back to view your data it should reappear, unless it or the flash drive has been corrupted in some way. Hope this helps.