Can't register ebook

I have been trying for several days to register an ebook. Every time I try,
I get the error:

ebook pro could not contact the server.
This could be caused by firewall/proxy or antivirus program you may be using.

I can de-installed everything I can think of, turned off windows firewall, had a friend look at registry.

He can dial up and register fine. Must be some hidden file on this machine. Any suggestions on how to find out what one, and delete it?

Thanks,
confused