hello allegroclitoris, you may have malicious addons present. please perform all these steps:

1. reset firefox (this will keep your bookmarks and passwords)
2. afterwards go to the firefox menu ≡ > addons > extensions and in case there are still extensions listed there, disable them.
3. finally run a full scan of your system with different security tools like the free version of malwarebytes and adwcleaner to make sure that adware isn't present in other places of your system as well.

Troubleshoot Firefox issues caused by malware

ps: it is necessary to have a support account so that you can get notified via mail once there are updates in the questions that you have asked.

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All of them.

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).

allegroclitoris said

Hi, I have what is seems to be a virus when I use Firefox, not with other browser. It keeps offering me deals and will scan the page I'm surfing on underlining key words and link them to other pages. It also keep offering me to take a Survey. McAfee and Trend Micro are telling me that my computer doesn't have a virus and I did a backup update twice (I went as far as Windows let me go in time) but it is still there. Can you guys help me? thank you, P.S. Why do I need an account to get support??? I understand that practice from other major corporations but I thought Mozilla was different...

Thank you it worked. I previously used Hitman Pro to scan for malwares but it didn't work as well as MalWareBytes.

allegroclitoris said

Thank you it worked. I previously used Hitman Pro to scan for malwares but it didn't work as well as MalWareBytes.

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

Your computer may get infected by adware. You can remove it manually by clear its related add-ons/extension and remove it form control panel if it is there. Then reset default Mozilla firefox. Also, you can remove it automatically by downloading anti-virus program.

However, using security tool can prevent your computer from virus as browser redirects and adware when you are surfing the internet, espectially unknown sites.