How does Ghost crash? Is there a specific error message?
As you are running Ghost under windows, presumably you are hot imaging.
What version of Windows are you running on?
Are you able to copy to the external hard disk from within windows?
Looking back over this thread, you have not provided very much in the way of detail about your hardware and software setup, so at the moment it's just a guessing game.
From a normal diagnostic perspective, have you ensured that your windows drivers are all at the latest available revision? Have you checked bios settings for USB devices?
You may also find that the USB to SATA adaptor may not be entirely compatible especially if it is a cheap Chinese import. Have you tried with an external 500Gb drive that is natively USB ?