How to delete in 3tb in external hard drive windows xp

Assuming you have 32 bit XP, it can't. XP does not support GPT partitions. If it sees the disk at all, it probably isn't showing the full size of the drive.

Q. Can the 32-bit version of Windows XP read, write, and boot from GPT disks?

A. No. The 32-bit version will see only the Protective MBR. The EE partition will not be mounted or otherwise exposed to application software.


http://msdn.microsoft.com/en-us/library/windows/hardware/gg463525.aspx