When you use Sysprep to install a Windows XP image, the Default User profile may NOT be consistently updated. New users profiles do NOT receive the customizations specified in the Winbom.ini file.
When the first user who is a member of the Administrators group logs on after installing or upgrading to Windows XP, that user's profile is modified to indicate that it has already completed Setup. When Sysprep runs, it copies that user's profile to the Default profile that is to be used to create new user profile. When the Mini-Setup Wizard runs on the destination computer, it doesn't apply the Winbom.ini settings because the Default User profile is marked as already completed Setup.
Before you run Sysprep on the source computer, use the Load Hive command in Regedit.exe to load the NtUser.dat file from Documents and Settings\Default User. Manually modify settings in the registry and then Unload Hive. Run Sysprep to create the disk image.
See the following Microsoft Knowledge Base articles: