Here is an easy step to upgrade to windows 7 SP 1. It’s a major release of Microsoft for windows 7 and is completely free. Just download the link below based on your operating system architecture and install. It will take awhile to install and after few restart, your windows will be upgraded to windows 7 SP 1.

For 32 bit(537.8MB)

For 64 bit(903.2MB) 

After restarting, you can right click my computer to see the windows edition option to view windows 7 update details.