Managing Windows Installer
Windows Installer provides a number of policies for managing how it installs applications and interacts with users:
User Configuration\Administrative Templates\Windows Components \Windows Installer (HKCU\Software\Policies\Microsoft\Windows \Installer)
Always Install With Elevated Privileges (AlwaysInstallElevated)
Directs Windows Installer to use system permissions when it installs any program on the system. You must also set the per-computer version of this policy for it to work.
Search Order (SearchOrder). Specifies the order in which Windows Installer searches for installation files. In other words, you can specify the order in which it looks at network, local media, and Web locations for installation files.
Prohibit Rollback ...