Viruses can be tough adversaries. If you haven't already, you may want to run some supplemental scanners. These three tools are highly regarded (and free): * Malwarebytes Anti-malware : http://www.malwarebytes.org/products/malwarebytes_free * AdwCleaner : http://www.bleepingcomputer.com/download/adwcleaner/ ''(ignore banner ads for other products)'' * SUPERAntiSpyware : http://www.superantispyware.com/ Within Firefox, problem usually arise among the Extensions and when your settings keep reverting when you restart the browser, in a user.js file. These articles should help in tracking those down: * [[Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems]] - I'd skip to the disable all section * [[How to fix preferences that won't save]]

You can check the target command line in the Properties of Firefox desktop shortcut to make sure that nothing is appended.