During the installation process, all browsers "Internet Explorer, Mozilla, Opera" will ask whether you want them to be your default browser or not.

Here i am providing how you could change the default browser once a browser is installed on your system:

Internet Explorer:

• Select “Tools | Internet Options” from the main menu in Explorer.
• Change to the “Programs” tab.
• Check the “Internet Explorer should check to see whether it is the default browser” option.
• Click “OK“.
• Close all Explorer windows and restart the system. Once the system comes back up, restart Explorer.
• When the “Would you like to make [Internet Explorer] your default browser?” prompt appears, click “Yes” to make Explorer the default browser.

Mozilla:

• Select “Edit | Preferences” from the main menu in Mozilla.
• Change to the “Navigator” tab/section.
• Click the “Set Default Browser” button.
• Click “OK“
• Close all Mozilla windows (for best results, restart the system). Finally, restart Mozilla.

Firefox:

• Select “Tools | Options” from the main menu in Firefox.
• Change to the “General” tab/section.
• Check the “Firefox should check to see if it is the default browser when starting” option.
• Click “OK“
• Close all Firefox windows (for best results, restart the system). Finally, restart Firefox.
• When the “Would you like to make [Firefox] your default browser?” prompt appears, click “Yes” to make Firefox the default browser.

Firebird:

• Select “Tools | Options” from the main menu in Firebird.
• Change to the “General” tab/section.
• Click the “Set Default Browser” button.
• Click “OK“
• Close all Firebird windows (for best results, restart the system). Finally, restart Firebird.

Netscape:

• Select “Edit | Preferences” from the main menu in Netscape.
• Change to the “Navigator” tab/section.
• Click the “Set Default Browser” button.
• Click “OK“
• Close all Netscape windows (for best results, restart the system). Finally, restart Netscape.
• When the “Netscape 7.x is not currently set as your default browser. Would you like to make it your default browser?” prompt appears, click “Yes” to make Netscape the default browser.

Opera:

• Select "File | Preferences" from the main menu in Opera.
• Change to the "Default Application" tab.
• Check the "Check if Opera is default browser on startup" option.
• Click "OK"
• Close all Opera windows (for best results, restart the system). Finally, restart Opera.
• When the "Would you like to use Opera as your default application for viewing web pages?" prompt appears, click "Yes" to make Opera the default browser.