For a successful installation of the Service Pack (SP1) on Windows 7, possibly, you need to have some prerequisites such as System Update Readiness Tool, enough disk space, disabling antivirus program, etc. If you got an “Installation was not successful” error message when installing a service pack on Windows 7 and/ or Windows Server 2008 R2, the following troubleshooting guides published by Microsoft may help you. The above guides certainly helpful if you have any plans to install the upcoming service pack or Windows update for Windows 7 or Windows Server 2008.