Service Pack 1 for Windows 7 arrived back in February 2011 and most of us have either downloaded it manually or through Windows Updates. The Windows installation disk which we've been using till now does not have SP1 integrated to it. Here are links from where you can download a bootable ISO image of Windows 7 with Service Pack 1.
- Windows 7 Home Premium with SP1 - 32-bit / 64-bit
- Windows 7 Professional with SP1 - 32-bit / 64-bit
- Windows 7 Ultimate with SP1 - 32-bit / 64-bit
Rest assured, these downloads are perfectly legal as long as you have a license key to use with them after the trial period. If you don't own a license key already, you can easily purchase one from here.