If you ever get short of disk space, delete the backup file(s) that we made under C:\Windows\system32\config, but I would keep at least one unless you really need to get rid of them, just in case something goes wrong with the one that we have in use at the moment.
800B010B is a strange error, I've never come across one of those before, but at least it's a little more informative than the errors for your missing C Marks.
Could you download this file please: https://dl.dropbox.com/u/16537616/NDP40-KB2729449.msp
Right click > Properties > Digital Signatures > Click on the entry > Details > View Certificate > Install Certificate.
Then reboot, and try updating again please.