remove 'ads by capricornus'
Recently Firefox has been tyaken over 'ads by capricornus,' whereby ads keep emergi8ng as new web pages. Also, ads pop up in sites that I want to see and block viewing.
I have Mcafee Total Protection.
Help
Reghards
Opaite Mbohovái (3)
You may have ad / mal-ware. Further information can be found in the Troubleshoot Firefox issues caused by malware article.
Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.
Adblock Plus {web link} Blocks annoying video ads on YouTube, Facebook ads, banners and much more. Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
Adblock Plus Pop-up Addon {web link} Adblock Plus Pop-up Addon extends the blocking functionality of Adblock Plus to those annoying pop-up windows that open on mouse clicks and other user actions.
Forum; Adblock Plus Homepage {web link}
It sounds like your Firefox installation got taken over by malware. I'd suggest these steps: