Service Pack 2 install error 0x800f0823

I'm trying to install Vista Home Premium SP2 via Windows Update, but then
quickly it says that "installation is successful" and it does -not- update
to SP2 (control panel still shows SP1) and then the SP2 re-appears in the
Windows Update.

So I tried going to the Microsoft download site and attempted to install the
standalone Vista SP2. I receive a dialog with "an unknown error has
occurred: 0x800f0823."

I found several other people have the exact same problem, and no solution.
Is Microsoft going to issue a patch to fix this bug?? System file checker
via command prompt shows good system file integrity. This system is really
clean, not many apps installed other than the Vista and some basic programs.
So maybe Microsoft can address the goof up?

The solution offered here has purportedly worked for some:
http://support.microsoft.com/kb/946078

Error message when you install an .msu update package on a computer that is
running Windows Vista: "The Windows Modules Installer must be updated before
you can install this package"
http://support.microsoft.com/kb/925316

That did not work for me with either the Windows Update or the download
standalone method of installation. Same error.

TaurArian, there is no Windows Module Installer available from within
Windows Update, so I'm not sure what that article is talking about. This
computer already has all of the latest Vista updates except for SP2. This
appears to be a major Microsoft bug with no apparent resolution, I hope MS
gets their act together..

A suggestion here:
http://social.answers.microsoft.com/...a-887b5be21c17

and
http://social.answers.microsoft.com/...-84832b8c4101/

It's not MS' problem, it's your problem. SP2 installed fine for me.
Did you have SP1 installed first?
What version of Vista are you running (Basic, Premium, Ultimate)?
Are you running 32 bit or 64 bit?
Does it show Service Pack 1 (or 2) when you right click My Computer and
select Properties?

thanks Taur, I tried these steps earlier when I found the same posts, except
I don't get any errors reported in the system file checker scan. I also
tried stopping the services mentioned and regsvr32 that long list of DLLs.
Still same error during standalone install of SP2. I haven't tried renaming
Catroot2, that's the only thing left to try.. and I'll post back here if it
works (but kinda doubt it since I tried so many other things).

I had SP1 installed first
Vista Home Premium
32 bit
It continues to show SP1 in system properties (even immediately after
Windows Update erroneously says that the update was successful) The
standalone installer however reveals the error code.

Ah, mine installed fine but I have the 64 bit Home Premium.
They have a different service pack for the 32 bit and the 64 bit. I assume
you downloaded the right one.
Do the service packs show up under Programs under the Control Panel?
You might try uninstalling both (assuming it lets you) and reinstalling
starting with SP1.

The solution is: install any original Vista SP1 DVD and choose "update" insert your own licence number. After installing the OS Vista SP1 update your computer by MSupdate. After this update there will be an automatic update to SP2. There are no outer solutions. Succes!