Antivirus and antimalware software: FAQ Content provided by Microsoft Applies to: SecurityWindows Select Product Version All Products Here are answers to common questions about Microsoft security software, including updates, where to download, and common software errors. What's the difference between a full scan and quick scan? When running a full scan, my PC freezes or hangs What does it mean when a threat is "partially removed"? Should I run Microsoft security software at the same time as other security products? What's the difference between Windows Security in Windows 10, Windows Defender in Windows 10 and Windows 8.1, and Windows Defender for Windows 7 and Windows Vista? Can I use Windows Defender Antivirus and Microsoft Security Essentials at the same time? How do I turn off, disable, or enable Windows Defender Antivirus? What is Microsoft security software? How do I update my Microsoft security software? What should I do if my security software detects a threat? Should I remove, quarantine, or allow a threat? How do I review a quarantined file? What do the alert levels in my security software mean? How do I scan a removable drive, such as a USB flash drive? How do I get rid of warnings about files I know are safe? What are definitions? Where can I see the change log, which is a list of the most recent updates? How do I know if I have a 64-bit or 32-bit operating system? I can’t update my security software Where can I get more help with malware and virus infections? What is Windows XP end of support? Last Updated: Jun 6, 2019 Need more help? Search No results Join the discussion Ask the community Get support Contact Us Was this information helpful? Yes No Tell us what we can do to improve the article Submit Thanks! Your feedback will help us improve the support experience.