The default browser for Windows XP resets whenever installing a new browser. For 64-bit Windows XP systems, both the 64-bit version of Internet Explorer and the 32-bit version are installed with the 64-bit version the default for Internet access and files. To set the 32-bit version of Internet Explorer as the default browser the setting defaults needs to be changed in the Windows Control Panel. Once the default is set, other browsers will ask if you want to change the default. Clicking "No" will leave the default set to the browser you chose.
Click "Start" and choose "Set Program Access and Defaults." This will open the Add and Remove Programs window.
Click on the double arrow next to Custom. This will expand a list of options.
Look for "Choose a Default Web Browser." Click on "Internet Explorer 32-Bit" and click "OK."