Thunderbird help will get you to the right area.
For Chrome, click the "three bars" icon top right, Settings, look at the "On startup" and probably edit "set pages.
In the "Search" area, set the search engine and also "Manage search engines..."
In Firefox, click dropdown "Firefox" tab top left, then Options, Options again,
Also check the "Extensions" via the "Manage Add-ons".
That should get you started. And stop downloading emoticon programs
