Changing the default browser is relatively easy in Windows XP. In order to change the default browser i will present a universal method that is applicable to any type of browser, whether you want to set as start browser: Mozilla Firefox, Google Chrome, Internet Explorer, Opera, Safari or any other.
The method below is universally valid regardless of the chosen default browser and is intended for Windows XP:
1. Go to Start
2. Click on Control Panel
3. Go to Add / Remove Programs
4. On the left click on Set Program Access and Defaults
5. Right click on the Custom
6. This opens a list of settings for Custom
7. Jump to Choose the Default Web Browser and choose the desired browser from the list
8. Press OK

Now the operating system will recognize the browser selected from the list as the default browser