Should one remove Windows Defender before installing an antivirus program?
For Windows 10, 8.1 and 8 - Windows Defender = Built-in Antivirus + Antispyware Protection. If you install a third-party Antivirus or Security Suite, it will automatically be disabled. Although in some cases it doesn't and requires manual procedures, as instructed in a previous post.
Windows Defender cannot be uninstalled, only disabled.
For Windows 7 and Vista - Windows Defender = Built-in Antispyware Protection (previously GIANT Antispyware). If you install Microsoft Security Essentials, it will automatically be disabled. You can manually disable Windows Defender if you choose other third-party Antivirus software.
Windows Defender cannot be uninstalled, only disabled.
Microsoft Security Essentials can be installed on Windows XP, Vista and 7, and is an Antivirus + Antispyware software for Windows. It cannot be installed on Windows 8, 8.1 or 10.
Microsoft Security Essentials is equivalent to 'Windows Defender on Windows 8.1' and 10. Windows 8 does not have the Network Inspection Service, as seen in later versions of Windows Defender and Microsoft Security Essentials.
Windows 7 was released in 2009.