A bundled program reinstalls it. Go to control panel and uninstall programs looking suspicious or related to coupons, ads, etc. Get rid of everything coupons related in FF plugins too.

Tried everything, erased all add ons and also a couple of plug ins that looked suspicious, exactly as you said, but the HD Plus continues to reappear every time I log in to FF, i remove it ad disable it, but it still reappears!!!!

Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.

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!

no malware, I have microsoft security essentials, and yet the HD Plus keeps coming back.

Did you use any of the anti-mal-ware programs? You should use at least three of them because each does its job a different way. One may miss something that another will pick up.

Thanks, solved now. I used the microsoft and it showed 0 problems, but when you mentioned that I should use at least 3, and sure enough Malware bytes discovered hundreds of HD Plus malware, then I ran ESET and found a few more, and finally hitman pro to finally clean all my malware. I noticed that HD Plus is not showing up again.

Glad to hear it. Nice going.