Microsoft is ending support for Windows 7 RTM , the original version released to manufacturers without a service pack update, on April 9, 2013. A service pack is an update meant to fix issues with the operating system.
Service Pack 1 for Windows 7 was released nearly two years ago and many, if not most, users will have already updated. If you’ve already added SP1, you will not be affected. To ensure as many people as possible get the service pack update before support ends, Microsoft has added Service Pack 1 to Windows Auto Update. Previously, Service Pack 1 required an action by the computer user to download and install, now it will download and install automatically if a computer is set up for automatic Windows updates.
Service pack can take a lot of disk space to install, ( up to 7400 MB downloaded from Microsoft website or up to 1050 MB through Windows Update) so you’ll need to make sure you have enough disk space available at least during the installation. You will get some of that space back after it’s done installing. It is pretty large and can take longer than most updates to install. If you have a laptop, you’ll want to make sure it’s plugged in. No point in draining your battery. If you don’t install SP1, your computer will still function, but won’t be able to install new security updates and bug fixes for Windows 7.
Mainstream support for Windows 7 with the service pack update will continue to 2015 and extended support for Windows 7 Enterprise and Professional will continue until 2020.
You can read more about Microsoft security patches and how to set up automatic Windows updates in this article.