To ensure that no other program interferes with the installation, save all work and close all other programs. The Taskbar should be clear of applications before proceeding.
Download the SOASST-01198104-US.EXE file to a temporary or download directory (please note this directory for reference).
Go to the directory where the file was downloaded and double-click the SOASST-01198104-US.EXE file to begin the installation.
At the "SonicStage Upgrade Program for Microsoft® Windows® 2000 and XP" screen, click "Next".
At the "License Agreement" dialog, read the agreement, then, if you agree, click "I Agree" to continue with the installation.
NOTE: Several setup boxes may briefly appear during the installation. As the files are installed, these boxes will close automatically.
At the "Finish" dialog, click "Finish", then click "OK" to restart the computer.
After the computer restarts, the installation of the Sony® SoniceStage® Upgrade Program is complete.

This utility installs an updated version of Sony® SonicStage® software and provides the following enhancements:
DSEE (Digital Sound Enhancement Engine)
HE-AAC codec support
CD Ripping in HE-AAC format

http://esupport.sony.com/US/p/swu-matrix.pl?upd_id=2343