If you installed AVG antivirus recently, you may observe AVG Secure Search showing the search results when searched from Firefox navigation bar instead of default search engine set by user such as Google, this is due install of AVG Security Toolbar in your Computer. Even though you uninstalled AVG and its toolbar you’ll get search results by AVG Secure Search. Here is how to remove AVG Secure Search as a Search Engine and let your default search engine to search for you from location bar.
#1. First make sure default search engine is selected and enabled from the search bar in Firefox.
#2. Remove AVG related extensions if any still exists and appear in Firefox browser.
Removing AVG Secure Search from Firefox
1. Type “about:config” in the address bar and proceed by agreeing to the warning.
2. Now type keyword.URL in the Filter box
3. Right-click on the Keyword.URL preference shown and click Reset button.
This will fix the things. Now go ahead and select and Reset the values for the below entries.
Update: With AVG 2013 installation, AVG Secure Search will be set as default search engine and home page for Chrome, IE and Firefox browser. To completely remove AVG Secure Search and its related components from your system and affected browsers follow the below link.