Just start the command prompt by entering cmd in Start->Run and run the following command to extract the source of SDK 3.1 (depending on your Windows verson and language).
Windows XP (English): --------------------- java -jar "C:\Program Files\Adobe\Flex Builder 3\sdks\3.1.0\lib\DMV-source.jar" "C:\Documents and Settings\All Users\Application Data\Adobe\Flex" "C:\Program Files\Adobe\Flex Builder 3\sdks\3.1.0" Windows XP (German): -------------------- java -jar "C:\Programme\Adobe\Flex Builder 3\sdks\3.1.0\lib\DMV-source.jar" "C:\Dokumente und Einstellungen\All Users\Anwendungsdaten\Adobe\Flex" "C:\Programme\Adobe\Flex Builder 3\sdks\3.1.0" Windows Vista: -------------- java -jar "C:\Program Files\Adobe\Flex Builder 3\sdks\3.1.0\lib\DMV-source.jar" "C:\ProgramData\Adobe\Flex" "C:\Program Files\Adobe\Flex Builder 3\sdks\3.1.0"
