Just for the record - GHS files are NOT from the Norton Ghost product, at least not any recent version. They are files generated by Ghost Solution Suite, which is the corporate product based on the original Ghost technology. Modern Norton Ghost, the retail product, is based on the old Partition Magic product which Symantec also acquired at some point. There is a separate Norton Community to which you can find a link in one of the sticky postings at the top of this forum.
I would recommend that you enlist the help of someone who has a standard PC, rather than a MAC, and who also has experience of the Ghost products. If you can provide an indication of where you are in the world, there may be a forum member nearby who can help.