If you are getting advertisements that are not generated by the sites that you are visiting, you may have some malware installed. Try running several malware scanners. It is best to run several as each will pick up things that the others miss. Some scanners you can try are: * Malwarebytes - http://www.malwarebytes.org/mbam.php * SuperAntiSpyware - http://www.superantispyware.com * Ad-Aware - http://www.lavasoft.com/products/ad_aware_free.php * Windows Defender - http://www.microsoft.com/windows/products/winfamily/defender/default.mspx * Spybot S&D - http://www.safer-networking.org/en/home/index.html