Do I have Windows Defender on my computer?.What happens if I disable Windows Defender?.Should I turn off Windows Defender if I have antivirus?.How do I completely disable Windows Defender?.Installing a third-party Antivirus Program.Method 1: Through Windows Settings or Windows Security.Methods to disable the Windows Defender in Windows 10 PCs.Reason 2: The Microsoft Defender antivirus is using up a lot of resources.Reason 1: The Microsoft Defender antivirus is preventing you from downloading or running certain programs.Reasons to disable the Windows Defender Antivirus on your Windows 10 computer.