Unwanted pop-ups, mystery toolbars, and how to scan without panic.
Start with the closest symptom
These guides are grouped here because the first checks overlap. Open the guide that best matches what you see now, then use its verification section before moving to a broader fix.
Full-screen "your PC is infected" pages, fake Microsoft phone numbers, and lock-screens in the browser are scams, close them without calling or installing their "fixer."
Related tools
Password Strength Checker, Check password characteristics in your browser. Nothing is sent to our server. This is guidance, not a guarantee.