Assuming the file is clean, here is the typical deployment method:
Assuming you have legally acquired a product key and wish to install this specific build, here is an optimized workflow.
The container. An ISO image is a sector-by-sector copy of an optical disc. This file, when written to a USB drive (using Rufus, Ventoy, or dd) or burned to a dual-layer DVD, becomes bootable media. win7-ult-sp1-x64-u-24535-esd.iso
In plain English: This is a bootable disc image for Windows 7 Ultimate Edition, 64-bit, with Service Pack 1 integrated, including a specific post-SP1 update rollup from build 24535 (circa 2016-2017), compressed aggressively in ESD format.
win7-ult-sp1-x64-u-24535-esd.iso is almost certainly not an official Microsoft distribution. Microsoft never released Windows 7 as an ESD in ISO format to the public. Therefore: Assuming the file is clean, here is the
If you need a legitimate Windows 7 ISO, Microsoft still provides them via the Software Download page if you input a genuine product key (though older keys may not work). Otherwise, use a known-good archive like the ones from Internet Archive with clear SHA-1 hashes and community vetting.
If you decide to acquire win7-ult-sp1-x64-u-24535-esd.iso from a non-Microsoft source (since Microsoft no longer distributes Windows 7 officially), you must verify its integrity and safety. win7-ult-sp1-x64-u-24535-esd
Upload the .esd file (or the extracted install.esd inside the ISO) to VirusTotal. Expect some "hacktool" or "patch" warnings if it includes activation bypasses, but verified clean images should have <5 detections (mostly false positives for Autounattend.xml or custom bootloaders).