: Open Windows Security → Virus & threat protection → Scan options → Full scan .
: Go to the Scan section → Custom Scan → Select all drives and check "Scan for rootkits" for the deepest possible check. 3. The "Deepest" Option: Offline Scanning :
: Shut down background applications to free up system resources and prevent file-locking conflicts.
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)
: Always update your virus database first. Scanning with old definitions is like a sheriff looking for outlaws with a 10-year-old "Wanted" poster.