and all the rest of the invasive ad-pages that I got when I tried to download Nikon Capture NX 2 for "free"
Try use addons to block popups/ads:
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 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.
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