What is Yahoo! Search Protection?
What is it?
Once Yahoo! Search Protection is enabled, and in order to protect your selection of Yahoo! as your default browser search engine setting, Yahoo! Search Protection may override previous search protection settings in other applications. When enabled, Yahoo! Search Protection logs changes you make to your default search settings as well as third party attempts to change your default search engine settings. Your default search must be Yahoo! in order for Yahoo! Search Protection to protect against changes to your default search engine. Enabling or turning on Yahoo! Search Protection will set Yahoo! as your default search engine. Yahoo! Search Protection comes with an update feature that will notify you when an update becomes available.
Typical installation path: C:\Program Files1\Yahoo!\SEARCH~1\
Description from the publisher“Yahoo! Search Protection will alert you if an attempt is made to change your default browser search engine from Yahoo! Yahoo! Search Protection is provided as an additional service to Yahoo! users through the installation process of the Yahoo! Toolbar download. Yahoo! Search Protection only works with Microsoft Internet Explorer. When a third party attempts to change Yahoo! as your default search engine, Yahoo! Search Protection will ask you to confirm the change and will prevent the change until you confirm it. Once you have chosen to block the change, Yahoo! Search Protection will automatically block the third party’s later attempts to change Yahoo! as your default search engine and will stop prompting you for this confirmation.”
Publisher about URL: http://info.yahoo.com/privacy/us/yahoo/srchprotect/details.html
Yahoo! Search Protection technical details
Name: Yahoo! Toolbar
Publisher: Yahoo! Inc.
Type: ActiveX Control
Class ID: {EF99BD32-C1FB-11D2-892F-0090271D4F88}
File: yt.dll
Folder: C:\Program Files\Yahoo!\Companion\Installs\cpn0
Name: Yahoo! Toolbar
Publisher: Yahoo! Inc.
Type: Toolbar
Class ID: {EF99BD32-C1FB-11D2-892F-0090271D4F88}
File: yt.dll
Folder: C:\Program Files\Yahoo!\Companion\Installs\cpn0
How to Automatically Uninstall Yahoo! Search Protection (with Boost)
If you you do not have Boost installed yet, download Boost and enjoy your PC.
Open Boost by either double-clicking the Boost icon 
in your notification area next to your PC's clock, or single-clicking the Boost icon and clicking the Open Boost button on the top left of the Boost notification window.
If you are not currently on the My PC screen of the main Boost window, click the My PC tab.
Click the Optimize programs button 
, this will launch the Program Optimization screen.
Locate the program in the list called Yahoo! Search Protection . (The program could be listed under any of the section such as Uninstall Recommended, Possible Uninstall, etc. based on how well Yahoo! Search Protection performs on your PC.)
Yahoo! Search Protection
To the right of the list item, click the Uninstall 
button and Boost will completely remove Yahoo! Search Protection from your PC.
How to Manually Uninstall Yahoo! Search Protection (with Windows)
Use Add/Remove Programs control panel in Windows makes to uninstall Yahoo! Search Protection. Follow the appropriate instructions below to use this control panel.
Windows 7
From the Start menu, select Control Panel.
In Large or Small icon view, click Programs and Features. If you're using Category view, under "Programs", click Uninstall a program.
Select Yahoo! Search Protection from the list of programs, and click Uninstall. Alternatively, right-click the program and select Uninstall.
Windows Vista
From the Start menu, select Control Panel.
In Classic View, double-click Programs and Features. In Control Panel Home view, under "Programs", click Uninstall a program.
Select Yahoo! Search Protection from the program list, and click Uninstall. Alternatively, right-click the program and select Uninstall.
Windows XP
From the Start menu, select Control Panel.
Click the Add or Remove Programs icon.
Select Yahoo! Search Protection from the list of programs and click Remove.