(See the best response by A.T.H.K.)
I cant download Byond 4.0. It says the file has been damaged, or the file does not exist .
Best response
Why are you downloading such an old version? - alternatively you can look here and try these.
Clear your browsing data and delete the damaged file and re-try to download.
Depending on the browser you're using, right click the download link and click to "save link as" or "save target as".