|  | Performing an Automated Installation Using Answer File and UDF Values During Setup
During Setup, keys and values are substituted between the answer file and the UDF, depending on the following scenarios: If a key is specified in the answer file but not in the UDF, the value specified in the answer file is used. If a key is not specified in the answer file but is specified in the UDF, the value specified in the UDF is used. If a key is specified in the answer file and also referenced by the unique ID in the UDF, the value specified in the UDF is used. If a key is not specified in the answer file and is specified in the UDF, but the value is left blank, no value will be used for that parameter. This might result in the user being prompted for the information. If a section or key is used in the UDF, but there is no section or key with that name in the answer file, Setup will create and use the UDF section.
| Note: For more information about substituting sections, keys, and values between the answer file and the UDF, see the Microsoft Windows XP Professional Resource Kit, and the Help files in the \\Tools\Deploy.cab folder on the Windows XP Professional compact disc.