When creating and deploying prestaged media using System Center Configuration Manager 2007, when the WIM comes back from the OEM on a new target machine the label of the C: drive on the target machine is set to the ID of the user that created the media.
NOTE See the following for more information about prestaged media: http://blogs.technet.com/b/configurationmgr/archive/2011/01/11/how-to-stage-task-sequence-prestaged-media-on-a-hard-drive-in-configuration-manager-2007.aspx