When installing Windows 7 Service Pack 1 (SP1), you might receive the following error message:
"Service Pack installation cannot continue"
"One or more system components that the service pack requires are missing."
This problem is commonly caused by using third-party products to customize a Windows 7 installation and remove some system components. To fix this problem, follow the steps below to reinstall Windows 7, and then try to install Windows 7 SP1 again.
Turn on your computer, and then do one of the following:
If you downloaded Windows 7, browse to the installation file you downloaded, and then double-click it.
Install Windows page, click Install now.
Click Get important updates for installation.
On the Please read the license terms page, if you accept the license terms, click I accept the license terms, and then click Next.
On the Which type of installation do you want? page, click Upgrade to begin the upgrade. You might see a compatibility report.
Follow the instructions to finish installing Windows 7.