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XP might need this little Registry tweak to overcome it's difficulty. Go Start then Run an din the Open box, type regedit then hit Enter. From th eFile menu, select Export then note the name and location of the backup you're about to creat - it may come in handy later.
When that's safely done, navigate to HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>Control >StorageDevicePolicies then double click to open Write Protected File and and change the value from a 1 to 0 Click OK and close the Registry from the File menu.
Restart the system and try the disk again.