Problem #1: When ordering Windows 8 Pro from the official site, the following had to be ignored to allow download:
atdmt.com
(There are about 17 entries associated with this address, there is probably only one that is the problem.)
Problem #2: Norton Internet Security's Auto-Fix will detect and remove the following entry:
om.symantec.com
(Does this need to be blocked seeing Norton is going to be removing it?)