I got the regular version working but the plus version gave the following error: Windows cannot access the specified devide, path, or file. you may not have the appropriate permissions to access the item.
Viewing post in OA New Dawn PLUS Update comments
Did some research on that error, it's not Ren'Py related, and what comes back from that error is, from what I gather that you do not have the permissions to open files on that drive? Or with the user you're logged in, try moving the folder into another SDD/HDD or try with another user? There are also rare instances, when at some point Ren'Py .exe's were flagged by Windows Defender and refused to open games, or some files might have been deleted.
Maybe download it again, and unzip it in another drive, and try run it with admin rights?