Mozilla does not scan your computer for viruses or malware and does not sell software. About the most Mozilla will do regarding security is let you check your browser plugins to see if any need to be updated. This is a free service. Please be aware that it is a very common scam on the internet to inform you that you have a security problem. Deceptive dialogs and fraudulent web sites will claim that everyone from Apple to Microsoft recommends their solution. Don't believe it. Make sure to use and install only trusted software on your PC. If you gave your credit card number or any login details to the scammers, please take appropriate actions to cancel the transaction and change your passwords. To clean any unwanted software of your PC, you can supplement your regular security software with these highly regarded free scanners: Malwarebytes Anti-malware : http://www.malwarebytes.org/products/malwarebytes_free SUPERAntiSpyware : http://www.superantispyware.com/ Hope that helps!!