4.0.5 will not open on my Windows 7

I downloaded 4.0.5 - my windows 7 says it can’t open the download package. It says ‘check installer’. How can I download the latest version or must I be content with Libre 3.6?

The computer tells me I am to check the installer for a valid windows installer. How am I to do that?

First of all, download the Windows Installer Cleanup Utilty, then remove windows installer from your computer (only if really necessary) download and install again (only if necessary) the latest version of Windows Installer.
This could fix your problem.