How can I check the current version of Windows Defender installed on my system?

You can view the Windows Defender version through the Windows Security panel by navigating to **Settings > About** and checking the 'Antimalware Client Version'. Alternatively, use the command line: `dir "C:\ProgramData\Microsoft\Windows Defender\Platform\" /od /ad /b` — the larger number indicates the latest version. For more details on Defender basics, see Penetration Basics - Windows Defender.