Okay so I downloaded a mod last night, and in the end it made my game too laggy to run, so I removed all the files it had put into my fh folder and the game would no longer open! It opens an initial black window, then closes again.
So what I did next is (thankfully I keep a backup of the original files in each folder) replaced the folder and it's contents with the original game contents, but I still had the same problem.
So what I did was uninstall the game, then I went to the download page only to find that it would not let me download it, but when I clicked on the download button it would redirect me to the homepage.... thankfully I still had the installer in my downloads folder from the last problem I had...
After uninstalling the game and reinstalling it, it works again, but I just wanted to let you know about the download redirect issue.