Dependent upon your Windows set-up, you might not be seeing the file extensions. You have the Steam version of the game, so look in your Steam Library folder. If you're familiar with using Windows File Manager, or File Explorer (the name is dependent upon the Windows version also), navigate into that Steam folder and find the game folder. On my one computer that I set up things like you did, it's "D:\Steam Library \Silent Hunter 4...", so just below the Lirbary folder. On another computer, where I put Steam and the game on the C: drive, it's C:\Games \Steam \SteamApps \common \Silent Hunter 4...". Once you find the game folder, click on the "View" tab at the top of the File Explorer, and then toward the upper right will be a "File name extensions" tick box. You might have to increase the size of your File Explorer window to see it all. But put a checkmark in that tick box, if there isn't one already, and you will then see "SH4.exe" and "SH4.ico" files in that folder. If you click on the "Details" choice for the display, you can then "sort" the files by clicking on "Type", and all of the executable files will group together just below the "act" type files. You should see the SH4.exe in that, along with the "SH4MissionEditor.exe" file.
If you don't have an SH4.exe in your Steam folder, then de-activate all your mods with JSGME. Once they are de-activated, then select the "MODS" folder, and use the <Ctrl><X> keyboard combination to "cut" the folder, then go up at least one folder level, or to the "root" of the drive and create a temporary folder, and then use <Ctrl><V> to paste the "MODS" folder into there for safekeeping. If you're not worried about losing the mods, disregard doing that. Then start your Steam app on your computer, and use its "Verify integrity of game files" from the "Local Files" dialog. That should bring everything back in. Put your MODS folder back in the game folder, or create a new one, and activate your mods again.
