Spent days trying to get to the bottom of this error. 0x80070005 apparently means “Access Denied”.
While researching the error and trying all the normal things you’d do to resolve a Windows Update issue I felt it was likely a NTFS / Registry permission error as I had also had issues on the laptop in question and Network Location Awareness which was eventually resolved by resetting some registry permissions. I googled for how to reset Windows NTFS and Registry permissions and found this…
secedit /configure /cfg %windir%\inf\defltbase.inf /db defltbase.sdb /verbose
which seemed to ring a bell, but alas it did not resolve my 0x80070005 issue. A day later whilst still trying to resolve this error I looked again for ways to reset Windows permissions and found this…
Solving setup errors by using the SubInACL tool to repair file and registry permissions
This instantly resolve the issue (without having to reset the machine or any services).
Other references found whilst trying to resolve the issue.
http://support.microsoft.com/kb/946928 – Information for network administrators about how to obtain the latest Windows Update Agent