That site does not sound like something that should be included in Firefox. Is this your first installation? If so, I suggest trashing the application and trying again from the official page at:

https://www.mozilla.org/firefox/all/#product-desktop-release

More info: How to download and install Firefox on Mac

Also, in case there is malware on your Mac that was somehow triggered by installing Firefox, see: Troubleshoot Firefox issues caused by malware.

There is a virus imbeded in the download for Firefox. I get a warning that Advanced Security blocked access to www.searchbaron.com. I am warned not to download Firefox. The virus is not in my computer but I get a warning when i download Firefox and try to use the browser. Virus is in the browser not on my computer. Fix please.

If you are going to say a Firefox download came with a virus, at least say where you downloaded it from and what version, for what OS and the language locale it is.

It sounds like you installed it fine but when you run Firefox it is trying to load that website?