It's an accident. You didn't realize installed another search engine on your firefox browser when you installed any program on your PC. This will change your default firefox search engine (example Google) to another search engine. You want to change back your default search engine to Google or another search engine that you like. But how to change default search engine on Firefox?
Google do not offers a search engine with the same facility from year to year. Google is always adding new facilities in their search engine. The goal is clear to make users more comfortable using google and did not switch to another search engine. There are some facilities provided by Google in their search engine that users may forget or never use. Though the facility is to help you in finding what you're looking for.
Here are some features of the Google search engine is worth a try.
You have a new site and I'm sure you want traffic. Who do not want traffic for the site? Everyone learn about how to get traffic to their site. From simple until difficult way. But how can I start to get traffic to my site?