Now you can download official Microsoft windows 7 (all editions) with service pack 1 (SP1) in iso format. This download is legal and free. Just download and burn the ISO image on a DVD, and you are ready to install windows 7 with SP1
what is service pack
This download is provided by Digital River. Digital River is an official Microsoft online distributor partner.
Below is direct download link of ISO file. These are bootable ISO image.
After downloading burn the iso image with any CD/DVD burning software. Now boot the computer using this DVD and install windows 7. All you will need is a license key to complete installation process.