where is windows defender located
Like many applications Windows Defender Installs itself in the Program Files Directory, If it has installed itself correctly then their should be a Windows Defender folder located there. This means that it has been installed. If it has been installed try running the Windows Defender Application Directly. Its named MSASCui.exe and is located as C:\Program Files\Windows Defender\MSASCui.exe. If this solves your problem, and Windows Defender runs, just hold down your CTRL key and drag a copy of MSASCui.exe to the STart menu.