New
#70
Hi and welcome to the Seven Forums :).
That's not an issue, you can either download an original Windows 7 install media and use it, or if you want to you can create an ISO Disk Image file from your ESD file and burn it to a DVD or a bootable USB stick.
Check this tutorial for download links for official Windows 7 install images: Clean Install Windows 7
To make an ISO image from your own ESD file, see this tutorial at our sister site the Ten Forums: ESD to ISO - Create Bootable ISO from Windows 10 ESD File - Windows 10 Forums. The tutorial works as is also with Windows 7and 8 ESD files.
For your project, this more in-depth walkthrough tutorial might give more tips: Windows 7 Image - Customize in Audit Mode with Sysprep
Kari