It can be frustrating when a program changes your default search provider, especially if the provider is changed without your permission. But you can stop this from happening. When a program such as an add-on or toolbar suggests changing your default search provider, Internet Explorer displays a dialog box that lets you decide whether to keep or change your current default provider.
If you want Internet Explorer to keep your default search provider and not prompt you again, select the Prevent programs from suggesting changes to my default search provider check box in the dialog box that appears when a program suggests a change.
You can also do the same thing by following these steps:
Open Internet Explorer by clicking the Start button . In the search box, type Internet Explorer, and then, in the list of results, click Internet Explorer.
Click the Tools button, and then click Manage Add-ons.
In Manage Add-ons, under Add-on types, click Search Providers.
Toward the bottom of the screen, select the Prevent programs from suggesting changes to my default search provider check box, and then click Close.