This is not from Mozilla or the Firefox web browser from say www.mozilla.org/firefox/all/

Mozilla does not do surveys for insert prizes like iPhones etc.

This may have been due to a Ad on some site that targeted some Firefox users as Yahoo pages have been a common place in last months.

How long have you had your current set of add-ons? Some of them may not be as trustworthy as one would hope. I suggest disabling all but the most essential for 24 hours to see whether that helps.

You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:

• Command+Shift+a (Windows: Ctrl+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions. Then cast a critical eye over the list on the right side. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything suspicious or that you just do not remember installing or why? If in doubt, disable (or remove).

Any improvement?