Instructions
Turn off the Xbox 360. Attach the hard drive to the hard drive bay on the left side of the Xbox 360. If you are copying the profile from another memory device (such as a Memory Card or USB flash drive), connect that device to the appropriate port. Turn on the Xbox 360.
Select the "My Xbox" tab. Select "System Settings." Select "Memory" on the System Settings menu. A list of memory devices connected to the Xbox will be displayed. Select the device that contains the profile you want to copy.
Select "Gamer Profiles" from the device menu. Select the name of the profile you want to copy. Select "Copy." Select "Xbox 360 Hard Drive" as the copy-to device. A notification will appear on screen when the process is complete.