Which security software (firewall) do you have? Make sure that Firefox has full and unrestricted permission to access internet. Clear the cache and the cookies from sites that cause problems. * "Clear the Cache": Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now" * "Remove the Cookies" from sites causing problems: Tools > Options > Privacy > Cookies: "Show Cookies" ---- You can still do a malware check with some more malware scanning programs.<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 /> * http://www.malwarebytes.org/mbam.php - Malwarebytes' Anti-Malware * http://www.superantispyware.com/ - SuperAntispyware * 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 * http://www.lavasoft.com/products/ad_aware_free.php - Ad-Aware Free See also: * "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked * [[Searches are redirected to another site]]

I tried everything mentioned in the post and I'm still having the same problem. I even uninstalled and reinstalled Mozilla. The funny thing is that this problem does not happen when I use Internet Explorer. I prefer Mozilla but I don't know what else to do.