You can select specific locations on your computer for Windows Defender to scan. However, if spyware or other potentially unwanted software is detected, Windows Defender will then run a quick scan so the detected items can be removed from other areas of your computer, if needed. 1. Open Windows Defender by clicking the Start button Picture of the Start button, clicking All Programs, and then clicking Windows Defender. 2. Click the down arrow next to the Scan button, and then click Custom Scan. Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation. 3. Click Scan selected drives and folders, and then click Select. 4. Select the drives and folders that you want to scan, and then click OK. Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation.