Cancel a Downloading Update
In order to prevent an update from installing, you need to wait for the file to complete downloading. Once this has been done it is a relatively simple task to remove the download file, thereby preventing Windows Update from trying to install the download. Follow these steps to cancel a Windows Update.
1. To begin, Go to Start → Run.
2. At the insertion point enter services.msc and click OK.
3. (Alternatively ignore 1 and 2 by right-clicking My Computer, selecting Manage and expanding Services and Applications to find Services).
4. In the main pane, right click on Automatic Updates and select Stop.
5. After the service is stopped, press Go to Start → Run.
6. This time enter %windir%\SoftwareDistribution and click OK.
7. An Explorer window will open, and you will see a list of folders - open the one called Download.
8. Delete the contents of the Download folder.
9. Close the window, then go back to Start → Run.
10. Again enter services.msc and click OK (or repeat 3.)
11. In the main pane, right click on Automatic Updates and select Start.
Now you have removed the downloaded updates, and Windows will no longer detect them. However they will more than likely be downloaded again at a later point.