Thanks a lot for your great description for this problem
Converting a GPT Data or Windows Disk to MBR/EMBRhttp://www.terabyteunlimited.com/kb/article.php?id=580
We used it today and had big problems, because Windows did not start after the procedure... and the Solution was simple:
Prerequisites: The *original Windows 7 System Recovery CD* should be created
If at step 23. Windows does not start, then just start with the original Windows 7 System Recovery CD and select to repair the boot files.
We tried everything else with fixmbr and those tools - none solved the problem.