When your Lumia phone with Windows Phone 8 software is connected to a computer running Windows XP, the phone may not be recognized if the computer does not have Service Pack 3. Instead, a USB connectivity error will be displayed, or the device might be recognized as an MTP device. To fix this, do the following:
1. First, install the latest Microsoft Windows XP Service Pack 3 to your PC. You can download the Windows XP Service Pack 3 from Windows Update or manually from the Microsoft web pages: http://www.microsoft.com/en-us/download/details.aspx?id=24
2. Next, install the latest Microsoft Windows Media Player 11 to your PC. You can download Windows Media Player 11 from the Microsoft web pages:
After this, reboot your PC and you will be able to browse files in your Lumia phone with Windows Phone 8 software using a USB cable and Windows Explorer.