Although not as effective as some dedicated anti-virus programs, Windows Defender does a reasonable job detecting and eliminating PC threats. That assumes, of course, that it’s kept updated. Furthermore, this anti-virus program is integrated into Windows 8 and 8.1 and is enabled on computers that don’t have third-party scanners installed, so it’s certainly the most convenient option around.
That said, Windows Defender lacks a scheduler and instead relies on the considerably less intuitive Windows Task Scheduler, so you might find yourself manually scanning more often than you like. The two preconfigured scan options are “Quick," which won’t necessarily pick up folders you’re specifically interested in, or “Full," which could poke along for hours before displaying results. Therefore, if you’re looking for a fast, comprehensive scan of only selected folders, the Custom option should be your go-to option.
Performing a custom scan allows you to specify exactly which folders should be scanned while omitting all others. This greatly speeds up the process when you, for example, only need to scan your download folder for recently acquired files. Now, it’s possible to tweak your registry to scan folders from File Explorer’s context menu, but that option only allows single-parent-folder scanning, whereas a custom scan can include as many folders as you like.