I don't know why someone would be running Windows 7 without Service Pack 1, but if you're one of those users, you might want to upgrade soon. Why? Because the end-of-support date for Windows 7 without Service Pack 1 installed is getting close.
On April 9, Windows 7 RTM (release to manufacturing), without Service Pack 1 installed, will no longer be supported. The news is coming from a post on the Microsoft Springboard Series blog. Support for specific Windows releases ends 24 months after the release of a Service Pack - and you guessed it - Windows 7 SP1 was released in February 2011, two years ago now.
Windows 7 SP1 mainstream (free) support continues until January 13, 2015 and extended (paid) support continues all the way up until January 14, 2020 for Windows 7 SP1. The Springboard blog includes the above chart which explains the differences between Mainstream and Extended support.