So, I just downloaded today and had no issues (so far)! I'm also running Win 10.
The steps I took were: Download the Zip > Make a designated folder for it > Drag the zipped file from Downloads folder to the designated folder I just created > Right click the zipped file and select "Extract Here" > Wait for that to finish > Delete the original zipped file and open the program.
WDYM you tried opening in 7z? All you should need to do is right click & extract the files. I recommend uninstalling/deleting all files associated with the program (including in your AppData folder in the Godot Folder) and redownloading the Zipped folder one more time to give it another whirl? Do you have enough space on your PC's main drive for the contents of the folder that shows up in AppData?