VMware vSphere

So I have this iso of Windows 10 and it works fine, I just wanted to edit a thing inside the iso, so I did that with infrarecorder and 7-zip. I tried using my edited iso but it would not boot up. I've looked up how to fix it but none of the answers helped. Thanks in advance. (this is vmware 15.1 iirc)

Editing "Bootable" ISO files is not trivial. I suspect that when you wrote a new ISO file with 7-ZIP the resulting image was not bootable, hence the "No OS" message.

Looking at something like this (https://www.nextofwindows.com/how-to-re-create-a-bootable-iso-from-extracted-windows-installation-files) might help you identify the steps where your edited image went wrong.

And just to state the obvious here, taking a once-bootable ISO and modifying it then finding it later unbootable is not a VMware-related issue and has nothing to do with Workstation or any other VMware product.