According to Microsoft, the WinHTTP AutoProxy, also known as autoproxy, feature has been available starting with WinHTTP version 5.1 in Windows 2000 Service Pack 3, Windows XP Service Pack 1 and Windows Server 2003. It runs as a service on local computers as well as on network servers. Autoproxy makes it easier for WinHTTP applications to configure necessary proxy settings. This feature takes away the responsibility of knowing proxy settings from the end user.
Right-click on "Computer" or "My Computer," and then select "Manage." This opens the Computer Management Console.
Click on "Services and Applications."
Click on "Services" from the "Services and Applications" tree. You now have three open windows inside the Computer Management Console.
Locate "WinHTTP Web Proxy Auto-Discovery Service" in the list in the center window. The list includes the services available on the local computer and is in alphabetical order.
Right-click on "WinHTTP Web Proxy Auto-Discovery Service," and select "Properties" from the pop-up menu. This opens the service's Properties window.
Go to the "General" tab, and under "Service Status," click on the "Stop" button. Click on "Apply." This stops the service within the current Windows session.
Click on the "Startup Type" combo box, select "Disabled," and click on "OK" to keep the service from starting automatically when you start Windows.
By default, this service doesn't start in a standard Windows installation. If the service is started and remains unused for more than 15 minutes, the system automatically detects the idle process and stops it. Stopping this service doesn't have any adverse effects on basic system functions.