Hi, I'm experiencing a serious problem on my Vista Basic Premium OS : since some weeks, I can't install/uninstall programs coming with a Windows Installer (*.msi) like Opera, Itunes, WLM, etc...Message telling me that Windows Installer it's not well installed and contact your administrator... I've searched a solution but I wasn't lucky enough, so I'm trying to post on different forums in order to have some help... Windows Installer v4 came with Vista and I know there's any downloading upgrade (I hope I'm wrong, but....). I've no more possibility to restore system and I wouldn't like to reinstall Vista... Any suggestions??? THX