Windows Vista Service Pack 1 (KB936330) Fails to install error code 800F0900

        I have my laptop setup to check for and install updates on its own so that I do not have to worry about it.  Apparrently Windows Vista Service Pack 1 (KB936330) was supposed to install itself on 07/22/08 and it failed.  Windows update has attempted to install this update every week since that day according to my update history and failed to do so.  Now my CPU is running at 100% without any applications running.  Trouble shooting the issue has shown that I need to install this update before i can check for any other updates.  Everytime I attempt to install this update it fails.  I recieve the error code 800F0900.  My latop is running on an Intel Celeron M 440 @ 1.86GHz processor with 2038MB of ram and a 32bit operating system that is currently running Windows Vista Home Basic.  Any help would be greatly appreciated.

Question Info

Last updated August 25, 2019 Views 50,088 Applies to:

System Update Readiness Tool Reporting Corruption…


If this CheckSUR.log is from after the SFC scan was run than you will need to perform an In-place Upgrade of the Operating System to resolve this issue. Should that fail to address the issue you will then need to perform a Clean Installation. However, prior to either reinstallation method I recommend that you perform a complete backup of any and all irreplaceable data – as there is always the potential for data loss when reinstalling.


Performing an In-Place Upgrade…


The following outlines the process for performing an in-place upgrade. After you have done this I strongly recommend that you install Windows Vista Service Pack 1 prior to performing any other changes. Should the inability to install this update persist after the in-place upgrade you would then need to perform a Clean Installation – however we will discuss that only if necessary.


Please let us know the results of this troubleshooting, and if you are still unable to install Service Pack 1.


How-to perform an In-Place Upgrade…

1.     Insert the Windows Vista Installation DVD into your computers DVD drive. Please note that you must do this will the system is running your existing version of Windows.

2.     One the Install Windows page click Install Now.

3.     On the Get important updates for installation page, we recommend getting the latest updates to help ensure a successful installation and to help protect your computer against security threats. You will need an Internet connection to get installation updates.

4.     On the Type your product key for activation page, we strongly recommend that you type your 25-character product key to help avoid problems during activation.

5.     On the Please read the license terms page, if you accept the license terms, click I accept the license terms.

6.     On the Which type of installation do you want? page, click Upgrade to begin the upgrade. You might see a compatibility report.

7.     Follow the remaining on-screen instructions.


Jared - Support Engineer - MSFT

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