The method you should use for the silent uninstall of the ANSYS Products 11.0 is as follows: 1) From a Command Prompt window or on the Start > Run menu type: setup.exe /r /f1 ”C:Uninstall.iss” where is the full path to the setup.exe file for ANSYS Products 11.0. In the GUI that opens select the Remove option and continue on with the uninstall. 2) Copy the C:Uninstall.iss file from the first machine to another machine where you would like to uninstall ANSYS (into the C: directory) and run the following command. setup.exe /s /f1 “C: Uninstall.ISS” /f2 “C: Uninstall.log” This will uninstall ANSYS and return a log file named “Uninstall.log” The procedure for doing a silent install of ANSYS Products 11.0 SP1 is given in the ANSYS Inc Installation Guide for Windows which you can find on our Customer Portal (http://www.ansys.com/customerportal/) under Product Information > Product Documentation.