: Open Windows Security → Virus & threat protection → Scan options → Full scan .
A "Deep Scan" (often called a Full Scan) goes beyond common folders to examine every bit of data on your storage drives. : virus scanner
: Shut down background applications to free up system resources and prevent file-locking conflicts. : Open Windows Security → Virus & threat
: Always update your virus database first. Scanning with old definitions is like a sheriff looking for outlaws with a 10-year-old "Wanted" poster. : Always update your virus database first
Some malware hides while the OS is running. Use Microsoft Defender Offline or a portable tool like Emsisoft Emergency Kit from a USB drive. This scans the system before the malware has a chance to "wake up". How to Run a Full Scan Using Windows Security
Whether you want to a deep scan or build a virus scanner from scratch, this guide covers the essential technical steps for both. Part 1: Running a Deep Scan (Advanced Users)