That's brought the problem down to a single error in the CBS log.
this in turn relates to another error...
2013-02-10 22:00:06, Error CBS Failed to process single phase execution. [HRESULT = 0x80070490 - ERROR_NOT_FOUND]
2013-02-10 22:00:06, Info CBS WER: Generating failure report for package: Package_for_KB2705219~31bf3856ad364e35~amd64~~188.8.131.52, status: 0x80070490, failure source: Execute, start state: Staged, target state: Installed, client id: WindowsUpdateAgent
2013-02-10 22:00:06, Info CBS Failed to query DisableWerReporting flag. Assuming not set... [HRESULT = 0x80070002 - ERROR_FILE_NOT_FOUND]
I think we may be able to resolve this one fairly simply I've uploaded a file - hstaa.zip - to my SkyDrive at Noel's SkyDrive
Please download and save it. Right-click on the saved file and select Extract all...
Change the target to C:\ and click on Extract
Close all windows (it would be a good idea to print these instructions!)
Now reboot to the Repair Environment - as soon as the machine restarts, start tapping F8 - this should bring up the Advanced Boot Menu, at the top of which should be the option 'Repair my Computer'
You'll have to log in with your username and password. Pick the option to use a Command Prompt
At the prompt type
hit the enter key - if you get a 'Not Found' error try
DIR E:\hstaa The drive letter in use when you find the folder will need to be substituted (for<drive>) into the following command... XCOPY <drive>:\hstaa <drive>:\windows\servicing\packages /y /i /s /v /h run the command (it should take almost no time)and when the prompt returns, type
and hit the Enter key to exit Command Prompt - reboot to Normal Mode Windows. Now run SFC /SCANNOW in an Elevated Command Prompt
then reboot and upload the new CBS.log file then, run a manual Check for Windows Updates. what happens?