Matthew Tundo from the Microsoft Embedded Team has created an excellent how-to for recreating an answer file from an already deployed Windows Embedded Standard 7 image.

This can be very useful in case you have only created the image with Image Build Wizard or in case you have created the image with Image Configuration Editor but lost the answer file.

The tutorial makes use of two tools:

• PkgScan
• TAP

With these two tools it is possible to retrieve the feature package and hardware information from the deployed file.
Using the created output files you are able to recreate your answer file in Image Configuration Editor.

For the complete how-to please visit the Microsoft Blog:
http://blogs.msdn.com/b/embedded/archive/2011/03/10/regenerating-answer-file-from-an-existing-device-using-pkgscn-and-tap.aspx