File Extension THEMEPACK File Format Windows 7 Theme Pack THEMEPACK stands for Windows 7 Theme Pack. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Performance degraded after changing optimizer mode IIS 4.0 How to partition a set of numbers into nearly equal bins.