You may loose any data or settings that is stored in the All Users folder, Default User folder, Start menu, Startup group, or Shared Documents folder, when your Windows XP was preinstalled by an OEM, and you perform any of the following:
1. You reinstall Windows XP in the same folder or do an in-place update.
2. You repair Windows XP by starting the computer from the CD-ROM and choosing R.
3. You upgrade the OEM version to a full retail version.
When you first start an preinstalled OEM version of Windows XP, a %Windir%\System32\undo_guimode.txt file is created. If this file is present when you perform any of the above actions, your data and settings will be lost.
To resolve the problem, delete the %Windir%\System32\undo_guimode.txt file before performing any of the above.
If you data is already lost, you must restore it from a backup.