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}

Hi, you may also find this useful - How to remove “Ads by OffersWizard” (Uninstall Guide) by Malware Tips.

I tried the steps detailed in the tips list. That didn't resolve my issues and popups continued. It wasn't until I installed and ran the malware software they recommended that I finally found the solution to my problem. I highly recommend you try the software and relieve the frustrations from the popups.

Thanks to FredMcD

Sorry to leave most important item the malware software recommended by Scribe that finally did the trick.

That was very good work. Well Done. Please flag your last post as Solved Problem so others will know.