I've just downloaded LibreOffice 4.1.3 (twice) on a newly refurbished Windows 7 Thinkpad. When I click the .msi to install, I get "This installation package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer package" 

How do I obtain a usable copy of LibreOffice for Windows?

I also tried 4.1.2 and 4.0.6 also, after 4.1.3 failed. 4.1.2 started fine, but encountered an error and failed to install. 4.0.6 fails in the same way as 4.1.3.

I have used 7-zip to test the 4.1.3 msi, and it is unable to open it ...