Possibly advertisements, or maybe you even have inadvertently downloaded and installed some search assistant or even malware. If it is a publicly available page give the URL/address and attach a screenshot. Does this happen on only one site or on many. If on many sites give a couple as examples. See * [[how do I create a screenshot of my problem?]] * [[remove a toolbar that has taken over your Firefox search or home page]] * [[troubleshoot Firefox issues caused by malware]] * a detailed reply about looking for malware [/questions/914980#answer-302372]

Do a malware check with some malware scanning programs on the Windows computer.<br /> You need to scan with all programs because each program detects different malware.<br /> Make sure that you update each program to get the latest version of their databases before doing a scan.<br /><br /> *http://www.malwarebytes.org/mbam.php - Malwarebytes' Anti-Malware *http://www.superantispyware.com/ - SuperAntispyware *http://www.microsoft.com/security/scanner/en-us/default.aspx - Microsoft Safety Scanner *http://www.microsoft.com/windows/products/winfamily/defender/default.mspx - Windows Defender: Home Page *http://www.safer-networking.org/en/index.html - Spybot Search & Destroy You can also do a check for a rootkit infection with TDSSKiller. *http://support.kaspersky.com/viruses/solutions?qid=208280684 See also: *"Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked