Windows System Defender is a new rogue antivirus software along the lines of Windows PC Defender (See the Windows PC Defender Removal guide) (I believe it’s the same family of malware.) It claims to be a powerful and effective antivirus and antispyware suite, but will overwhelm you with warnings and alerts and popups of security problems with your computer and more or less hold you hostage with the fear that your data is at risk unless you purchase their software. All of their scans are falsified and most likely the biggest thing wrong with your computer is having this rogue software installed. Read on for how to remove windows system defender.