When you purchase Windows 7 from Microsoft Store, you have the option to download an ISO file or compressed files. You have to burn that ISO file into a DVD for installation. If you plan to use a USB drive instead, the Windows 7 USB/DVD Download tool will allows you to create a copy of your Windows 7 ISO file on a USB flash drive as well as a DVD.
To create a bootable Windows 7 installation USB drive, launch the Windows 7 USB/DVD Download tool and follow the steps. It’s pretty straightforward – browse to locate the ISO file you downloaded and then choose either a USB or DVD and insert the same into the computer. Then wait as it copies the file to the removable medium.
To install Windows 7 from your USB flash drive or DVD, all you need to do is boot from the medium.
Windows 7 USB/DVD Download tool is from Microsoft.