Windows Update failure: NET START wuauserv -- Access is de..

Archived from groups: microsoft.public.windowsxp.security_admin (More info?)

I have yet another computer in which Windows Update is failing. This time it
give an error message I haven't seen before:

CONFIGURATION: Stand-Alone Windows XP SP2, all patches applied. Windows Update
worked well last patch Tuesday, in June. All tests run as administrator.

1) When running the command:
regsvr32 wuaueng.dll
as an administrator, I get the message:
DllRegisterServer in wuaueng.dll failed. Return code was: 0x80070005

2) When running the commands as an administrator:
net stop wuauserv
or
net start wuauserv
I get the message:
System error 5 has occurred. Access is denied.

3) Reloading Windows XP made no difference.

4) A variety of possible fixes are suggested. None of them worked. The key
issue seems to be that access is denied to the wuauserv service.

5) The suggested fixes in this article did not work:
http://support.microsoft.com/defau [...] -us;836926

6) When running Gpedit.msc and expanding the following items in the Local
Computer Policy list:
Computer Configuration/ Windows Settings/ Security Settings/

and left-clicking on "Local Policies", I get the error message:

"The Group Policy security settings that apply to this machine could not be
determined.

"The error returned when trying to retreive these settings from the local
security policy database (%windir%\security\database\secedit.sdb) was: The
parameter is incorrect.

"All local security settings will be displayed, but no indication will be
given as to whether or not a given security setting is defined by Group Policy.

"Any local security setting modified through this User Interface may
subsequently be overriden by domain-level policies."