Where are you downloading the browsers from?

Softonic has had issues with infections over the years. For most software I recommend that people go right to the manufacturers site. In this case Google. https://www.google.com/chrome/browser/desktop/
Firefox is available at https://www.mozilla.org/en-US/firefox/new/?product=firefox-3.6.8&os=osx%E2%8C%A9=en-US
Pale moon is available at https://www.palemoon.org/
Safari is no longer updated for windows so I would stay away from that.
Maxthon is available at http://www.maxthon.com/

There are more than 100 different browsers. Some are specific to Windows, others will not run on Windows. They cover many different uses and features. All of them should be downloaded from the authors site.

As for download pages, as you have found out, there are some out there that have been compromised in the past, and may still be. I use FileHippo or MajorGeeks if I can't find the authors site. If they do not have it, then I go to download.com but I have been staying away from that site, as they have their own downloader / installer.

Yes.

You are welcome!