So if IE, Chrome and Firefox, it would appear to be some sort of Windows 7 Problem. What I meant by installing the software locally was in repsonse to your first post "Speco is trying to download.." So, yes, I would contact the company. You are not likely the first person to try their software on a Windows 7 machine, and they may have a workaround.
Unknown Publisher Warning - June 2010 - Forums - CNET Mar 28, 2011 Help! Cant disable security warning, unknown publisher Apr 15, 2013 Windows says the install is from an unknown publisher Feb 27, 2019 Download file shows unknown Publisher - Adobe Support
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Apr 15, 2013 Windows says the install is from an unknown publisher
Jul 17, 2011
When running the Windows installer, Windows will display warning messages telling users that the PG-Desktop is from an unknown publisher. To remove the warnings, we need sign the code with Adobe's profile. The Inno API for code signing can be found here. hermwong added the windows label on … How to add publisher for setup - Stack Overflow