Having continuous ads popping up and rogue tabs opening up in Mozilla. OS is Windows Vista. I don't know exactly when this started; it's the PC used by my teens. Yeah, there's the problem.
I uninstalled various toolbars and anything I couldn't identify. I also uninstalled old security programs, installed and scanned with Microsoft Security Essentials, installed and ran Adwcleaner, installed and ran Malwarebytes. Problem persists.
Now I'm stumped. What do I do next?
Thanks for any help you can give!