hello velu_bah, this sounds like a problem possibly caused by adware/malware on your pc. please go to firefox > addons > extensions & remove any suspicious entries (toolbars, things that you have not installed intentionally, don't know what purpose they serve, etc). also go to the windows control panel / programs and remove all toolbars or potentially unwanted software from there and do a full scan of your system with the security software that you have in place and also a different tool like the [http://www.malwarebytes.org/products/malwarebytes_free free version of malwarebytes]. [[Troubleshoot Firefox issues caused by malware]] [[Remove a toolbar that has taken over your Firefox search or home page]]