must we choose windows defender

first let's see something about windows defender

The specific functions of Windows Defender include:
Redesigned and simplified user interface - Comprehensive customer feedback and redesigned the user interface of Windows Defender to complete common tasks more easily. Warning system can be adjusted according to the seriousness of the threat alert level, thereby reducing the overall number of alarms, but still be able to ensure that users will not miss the most urgent alerts.
Improved detection and removal - Based on the new engine, Windows Defender can detect and remove more from spyware and other potentially unwanted software the threat posed. Real-time protection has also been enhanced to better monitor key points in the operating system is changed.
The protection of all users - all users, regardless of whether they have administrative privileges, you can run Windows Defender. This ensures that all users are subject to the protection of Windows Defender.
Support 64-bit platforms and accessibility - Windows Defender supports the auxiliary function and 64-bit platforms. Make sure to use 64-bit platform WindowsDefenderX64.msi.
Delta definition updates - Windows Defender now downloads smaller delta definition updates downloaded and installed to reduce the time required for definition updates. Update their customers need to update the definition of the download time is even shorter.
Limited free support - As part of our commitment to customers as part of security, Microsoft provides two free support to resolve the Windows XP and Windows Server 2003 with Windows Defender related issues. Examples of effective support program, including installation, configuration, definition update, detection and removal errors. For more information, please see the Windows Defender support policy.
WGA enforcement measures - non-genuine Windows to run a big risk. Only genuine Windows customers can receive product downloads, Windows updates and special offers. Windows Defender will validate your installation before the Windows is genuine. Moreover, running non-genuine systems for computer, Windows Defender is only to eliminate a serious threat. Security level will be detected as low, medium and high threat, but unless Windows is genuine, it would not eliminate these threats. For more information, please visit the Windows Genuine Advantage.


but we should know that every antivirus software includes anti spyware. so there is no need to run windows defender. according to another report, windows defender can only stop50%---60%
spyware. so if you run vista, you need to run windows defender, for it will help you nothing but slow down you pc.