Windows 7 SP1 won't install

Hi there,
I have gone through so many previous posts on the subject but am unable to resolve my problem.
This morning I ran Windows Update and was informed that SP1 was available for download. I then downloaded the update (full) - it took seven hours! When I tried to install, I received an error message informing me that the install had been unsuccessful When I tried to reinstall, it started to download the files again. I aborted the process, and now desperately need some help.
I also have the full SP1 file which I downloaded earlier from the download site, but this also will not install.
I use Windows Security Essentials with Windows 7 64-bit Home Premium.
Please.....

Hello!

What error code are you receiving? Have you run the System Update Readiness Tool? If you have, can you also please upload C:\Windows\Logs\CBS\CheckSUR.persist.log?

Thanks!

Richard

Attached is the image of the message I received:
[IMG]c:\windows\users\rob\desktop\SP1 Message.jpg[/IMG]
And the file reads:


=================================
Checking System Update Readiness.
Binary Version 6.1.7600.20822
Package Version 10.0
2011-01-21 11:11

Checking Windows Servicing Packages

Checking Package Manifests and Catalogs

Checking Package Watchlist

Checking Component Watchlist

Checking Packages

Checking Component Store

Summary:
Seconds executed: 680
No errors detected


=================================
Checking System Update Readiness.
Binary Version 6.1.7600.20822
Package Version 10.0
2011-01-21 12:29

Checking Windows Servicing Packages

Checking Package Manifests and Catalogs

Checking Package Watchlist

Checking Component Watchlist

Checking Packages

Checking Component Store

Summary:
Seconds executed: 480
No errors detected

Hope all this works. Thanks for the interest - much appreciated.

Sorry - looks like the image doesn't upload. Message reads:
A system error prevented the service pack from installing. Please download and run the “Check for System Update Readiness” tool at Description of the System Update Readiness Tool for Windows Vista, for Windows Server 2008, for Windows 7, and for Windows Server 2008 R2.
If the “Check for System Update Readiness” tool doesn’t fix the problem, visit the Microsoft website for more information.

I have run the tool. Supposedly successfully after the message I received.

Help please - I am really desperate! I have the constant reminder that an important update (SP1) is waiting to be installed, but I cannot install it.
I have also downloaded the System Update Readiness Tool (Windows6.1-KB947821-v10-x64.msu) and tried to run it. I get the error message: Installer encountered an error: 0x8007000d. The data is invalid.

Do you have Daemon Tools installed by any chance, if you do uninstall it, reboot then try the update again.

No - Daemon Tools is not installed.

No - Firefox 4

It seems that no-one has an answer to this, I guess a re-load of OS is the way to go !