MTOW,
What was the last successful Ghost clone that you did? What is the version of Ghost that you are using? Are you sure that it supports XP?
What size is the original disk and what size is the new? Does your PC BIOS support the full size of your new disk?
I did a considerable amount of work with Ghost and Win2K / XP, although I was creating image files (as opposed to direct disk-disk cloning) which I multicasted to several destination PCs simultaneously. No problems with then booting all the "clones" - Sysprep was run on the master before taking the image.
If you have access to a 2nd computer with sufficient disk space to store the compressed image file from the source computer, you can then swap in the new hard disk and re-image it as the destination computer.