Click on Tools > Internet Options. Go to the Advanced tab. Click on the Reset button.
How to reset Opera?
Close all running instance of Opera. Go to the installation folder of Opera:C:\Users\user_name\AppData\Roaming\Opera\Opera\, provided that you have installed Opera using the default settings. Delete the Operapref.ini file
How to reset Google Chrome?
Close all running instances of Google Chrome.
Go to the installation folder of Google Chrome:
In the User Data folder, look for a file named as “Default” and rename it.
Launch Google Chrome and a new “Default ” file will be created.
On the latest version of Google Chrome, click on the Customize and control Google Chrome button > Settings.
Click on Advanced Settings.
Scroll down to the bottom of the page, until you reached the “Reset browser settings” section.
Click on Reset browser settings.
Rename the Default file, located in: ~/Library/Application Support/Google/Chrome/Default
Rename the Default file, located in: ~/.config/google-chrome/Default
How to reset Firefox?
Read this FAQ: Reset Firefox
How to reset Safari?
Click on the “Safari” in your Safari menu.
A drop-down menu will appear, simply click on the Reset Safari tab.
A warning dialog will appear pointing out what will be removed.
Click on the Reset button to complete the process.
Safari will restart automatically.