Unable to install Windows 7 Service Pack 1

I am unable to install Windows 7 Service Pack 1 on a desktop PC.  I get this error message:

Installation was not successful
"The referenced assembly could not be found"

I have tried running a couple utilities from Microsoft:

* Automatically reset Windows Update components
* System Update Readiness Tool for Windows 7 (KB947821) [August 2011]
* sfc.exe /scannow

I also updated the driver for the graphics card.

Any help would be greatly appreciated.

Thanks, Jon
Jonathan SuberIT DirectorAsked:
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Please check whether you have enough space in C: drive
*** Hopeleonie ***IT ManagerCommented:
I had the same problem last week. Did not find any fix. Only an In-Place Upgrade helped. You will loose nothing. But create a backup first.

How to:
Also Check the logs C:\Windows\Logs\CBS\CBS.log
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Reinstall the OS, then as the first thing install SP1 (unless of course the installation media is already on SP1).
Jonathan SuberIT DirectorAuthor Commented:
These are all good comments...thank you.

This error keeps showing up on my CBS.log:

Failed to get session package state for package: Package_2_for_KB3046480~31bf3856ad364e35~x86~~ [HRESULT = 0x80070490 - ERROR_NOT_FOUND]

I have removed this update and reinstalled it.  Still failed.

I can try an In-Place upgrade or repair but I want to exhaust all possible solutions before I do that.  This is an important PC on our network.
Just remove the update KB3046480  and try to update the service pack  without reinstalling it and then check the logs again
This has to be a fresh installation, otherwise you'd have had installed SP1 years ago. Support for Windows 7 without SP1 has ended a long time ago. An unsupported OS is completely insecure and subject to attacks caused by unpatched security holes etc. This could also be the cause for SP1 not being installable.

So the best fix is to do a fresh installation.

If it is already freshly installed, maybe something went wrong, and a new installation is fast anyway, so either way, do a fresh installation of the OS. You loose the least time that way.
Jonathan SuberIT DirectorAuthor Commented:
This PC has been running like this for a few years.  I just caught it when I was checking the browser encryption settings.  I am going to try to remove update KB3046480 and try to install SP1.  If that doesn't work, then I may not have a choice but a fresh install.  Thanks, Jon
If it has been running without SP1 for that long, your only sane option is a fresh install. Everything else is a waste of time, and you may carry over some nasties which may make it insecure even after the upgrade and which are very hard to remove.

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Jonathan SuberIT DirectorAuthor Commented:
I am ordering a new system for this user.  This system is from 2011 anyway.  I will reinstall the OS and re-purpose somewhere else.  

Thank you to all that commented.  I appreciate it.  Jon
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Windows 7

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