It is spam definitely. My WOT add-on came up; This came up.

Do a malware scan.

You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• TDSSKiller - AntiRootkit Utility
• Hitman Pro
• ESET Online Scanner

Microsoft Security Essentials is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one.

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Did this fix your problems? Please report back to us!

Thank you! MalwareBytes didn't seem to detect it on 9/18 with a full scan. Will try another, was able to block the site on Avast website block.

Look for a program Bonanzadeals in Control Panel, Unistall or Change a program. Delete this program. It is causing the problem.

Advice removed by a forum moderator. Please do not post links for paid for support. (Mozilla Support rules and guidelines )

This is a removal guide I have found that would appear to be genuine

• http://malwaretips.com/blogs/web-longfintuna-net-virus/

You may also find information on other reputable sites. Note should this be a new threat or name the reputable sites and tools may take some days to update the information.

Please scan with multiple newly updated tools and please report back if these work or if you find guides on reputable free support sites.

Here's a good read:

http://deletemalware.blogspot.com/2013/09/remove-longfintunanet-virus-removal.html

You should really do a malware scan because issues have been linked to a JavaScript-injected trojan type virus called Trojan:JS/Feebs.gen!D and probably some other badness like malicious web browser extensions. I recommend Malwarebytes and AdwClaner.

OK. Here is the manual guide that will explain how to remove adware applications and browser hijackers from your browser - http://www.system-tips.net/guide-to-fix-browser-redirection-and-remove-browser-hijackers/ You do not need to download any program there. Simply follow the manual guides, this should help you get rid of web.longfintuna.net virus.

Instead of using online malware removal guides that often link to 'pay-for-support' services or malware removal software that may or may not be legitimate, the safest route would be to ask for help on a trusted support forum specializing in malware removal. The Mozilla Support article, Troubleshoot Firefox issues caused by malware has recommendations in the How do I get rid of malware? section:

https://support.mozilla.org/kb/troubleshoot-firefox-issues-caused-malware#w_how-do-i-get-rid-of-malware