The clock on my test PC was off by 7 years (battery failure). This caused Windows Update to fail in the most bizare ways. I suggest to try an time-update before entering the Windows Update function. The wrong time probably also caused a lot of trouble with "Genuine Advantage".

NKJensen -Yep.. That'll do it... You might want to consider posting this in the "Have a Comment about Windows 7 RC (part 3)" thread - posts made there are routinely collected and sent to the development team. This probably would be a good thing to include in the final release...