If you have installed some unwanted toolbars in the firefox and you have installed it.
Still the site appears while you open a new tab.
you don't know how to remove it.
Here is the solution for the Firefox
- Open a new tab
- Type 'about:config' into the address bar
- Accept the warning
- Search for 'browser.newtab.url'
- Right click and choose reset
- The value should change to 'about:blank'