Few days back, soon after installing Internet Explorer 9 (Vista) - prevously I was running Internet Explorer 7 for six years but was performing erratically. After IE9 was installed - Troubles were noticed for non-functioning of Windows Installer Service. After obtainning guidelines from KB-942288, KB-929135 and KB-2438651, it appeared that my previously Installed Windows Installer was not accessable. Now after downloading Windows Installer 4.5 compatible to Vista 32-bit, it became problem to me to install the application. Because one message informs me --"THE SYSTEM ADMINISTRATOR HAS SET POLICIES TO PREVENT THIS INSTALLATION." How to modify those Set Policies so as to accommodate Downloading and Installations of all Microsoft and Non-Microsoft Applications ? Please suggest.