Addendum: As it turns out, Avast Internet Security wrongly considers msiexec.exe from Microsoft as malware and blocked me from installing software. It did not put it in the virus chest but consistently blocked any program that relies upon msiexec.exe to install, from actually installing. I was able to install programs if I disabled all shields until restart.
As it turns out, it also messes with Intuit Quicken Deluxe 2015, which it allows to install, but after installed and accessed my data file, upon subsequent openings of Quicken; revert to "Open a file/import a file/start new"