Hullo!
I made a small write up in my custom image thread. You don’t necessarily need to use my image, although you can. The instructions should be pretty much the same!
Look at the first post in the thread, and scroll down to the Installation section.
Another thing. You may need to update your Etcher, if that’s what you’ve used.
I don’t use windows, so can’t really help you with Win32.
Try a spare SD card. it could be a corrupt card. They tend to do that occasionally.