In one of our previous tutorials I've shown how Windows Defender works in Windows 7. For those of you who use other security solutions with similar or better functionality, it might be useful to know how this program can be turned off. In this article I will teach you how to turn Windows Defender on or off, depending of your needs.
How to Turn Off Windows Defender
Start Windows Defender and click on the Tools button.

Under the Settings section you will find the Options link. Click on it!

In this area you will find a lot of configuration options. Scroll down to the end of the list and click on Administrator. Deselect the 'Use this program' check-box and press the Save button.

NOTE: You will might receive an UAC (User Account Control) prompt. Click on Yes to continue.
Now you will receive a notification saying that 'This program is turned off'. Click Close.

How to Turn On Windows Defender
Open Control Panel in the Classic View, then click on the Windows Defender icon.

Windows 7 will notify you that the application it's turned off. Click on the 'click here to turn it on' link and Windows Defender will be enabled again.

NOTE: You can only turn Windows Defender on or off if you have administrative permissions. This setting will apply to all users defined on your computer.
Conclusion
As you could see from this tutorial, it is very easy to turn Windows Defender on or off. If you disable it, make sure that a proper security alternative is installed. For more information about this tool and how to secure your Windows computer, check the articles recommended below.
Related articles:
Windows Defender - How it Works in Windows 7
Windows Firewall - How it Works and How to Enable or Disable It
What is UAC & Why You Should Never Turn it Off