There is usually no need to use a registry cleaner.<br /> If you see that poop-up while visiting websites then that is most likely a simulation that is downloaded from internet and not showing a scan done on your computer.<br /> The intend of such a pop-up is to get you to buy their software and you should never respond to such an alert or you will be infected by malware. ---- Do a malware check with some 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 /> <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