If you're unsure of a download and not sure how to tell if a piece of software is virus ridden, post the link here and I can download / install and give an opinion as to whether or not the software is safe or not. As with anything, I'm not guaranteeing anying other than my ability as someone who knows the Windows OS. I have 25years of experience in the Software packaging / integration field. That being said, I downloaded a copy of Flexera Installshield, installed to a VM and it had a ton of Virus's in it. These are the things I can at least alert you to.
Also, If you can't get the software to install properly, I might be able to help with that too.
Also, If you can't get the software to install properly, I might be able to help with that too.