Your phone still appears as a yellow question mark in the Device Manager? It seems that Windows XP can't install the right drivers.
To manually download and install the Windows Phone driver:
1. Go to Microsoft Update Catalog
2. Search for "windows phone winusb." You should find "Windows Phone - Other hardware - WinUsb Device."
3. Tap or click Add in the right-most column.
4. Tap or click View basket (just below the search box).
5. On the Updates in your basket screen, tap or click the Download button. Tap or click the Browse button and select a convenient location to save the file, such as your Desktop or the Downloads folder. Tap or click Continue, and then tap or click Close when the file has downloaded.
6. Browse to the file you downloaded (which may be contained in a folder called "Windows Phone - Other hardware - WinUsb Device") and then double-tap or double-click it.
7. Double-tap or double-click the file winusbcompat.cat. Select a location (such as the Desktop) to extract the file.
8. Repeat the steps under Update your Windows Phone 8 driver above, but when you reach step K, browse to the file you just saved instead of the C:\Windows\Inf\ folder.
See also https://support.microsoft.com/en-us/kb/2749484 Step 4
To manually download and install the Windows Phone driver:
1. Go to Microsoft Update Catalog
2. Search for "windows phone winusb." You should find "Windows Phone - Other hardware - WinUsb Device."
3. Tap or click Add in the right-most column.
4. Tap or click View basket (just below the search box).
5. On the Updates in your basket screen, tap or click the Download button. Tap or click the Browse button and select a convenient location to save the file, such as your Desktop or the Downloads folder. Tap or click Continue, and then tap or click Close when the file has downloaded.
6. Browse to the file you downloaded (which may be contained in a folder called "Windows Phone - Other hardware - WinUsb Device") and then double-tap or double-click it.
7. Double-tap or double-click the file winusbcompat.cat. Select a location (such as the Desktop) to extract the file.
8. Repeat the steps under Update your Windows Phone 8 driver above, but when you reach step K, browse to the file you just saved instead of the C:\Windows\Inf\ folder.
See also https://support.microsoft.com/en-us/kb/2749484 Step 4