http://support.microsoft.com/default...b;en-us;307545
MS's work around.
I've had this before too...Can be done, but it may not work at worst case scenario.
Norton, as above, I avoid it at all costs.
Over the years, when errors happen like this, I just re-install Windows. After many times of spending hours to work around a re-install, I've just got used to re-install because it is the fastest way possible to get back up and running.
I have many partitions, so my data isn't wiped (learned by experience the hard way), just windows is wiped, but the pain is also to re-install all the other packages.
I know this may not be some people's "kettle of fish", but it is probably the better way to start afresh.