What Does This Do?
This utility installs the originally shipped version of the Ricoh® Memory Stick® Device Driver for Microsoft® Windows Vista® 32-bit version operating system.
For models that shipped with Microsoft Windows Vista 64-bit version, this file is provided for downgrade to Microsoft Windows Vista 32-bit operating system.

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 RIDMSC-15231200-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 RIDMSC-15231200-US.EXE file to begin the installation.
At the "Ricoh Memory Stick Disk Device" screen, click "Next".
At the "License Agreement" dialog, read the agreement, then, if you agree, click "I Agree" to continue with the installation.
At the "Finish" screen, click "Finish".
The installation of the Ricoh® Memory Stick® Device Driver is complete.

This utility installs the originally shipped version of the Ricoh® Memory Stick® Device Driver for Microsoft® Windows Vista® 32-bit version operating system.
For models that shipped with Microsoft Windows Vista 64-bit version, this file is provided for downgrade to Microsoft Windows Vista 32-bit operating system.

http://esupport.sony.com/US/p/swu-matrix.pl?upd_id=3629