One thing that you can try is to submerge your boat a bit ("sound" the bottom first, and don't hit it), then try to motor ahead. Once you get moving (if you do), then surface and see what happens. I am trying to remember what that is a symptom of, but the grey matter is - well, grey...
If you have any mods installed, you cannot have your game installed in one of the Windows "Program Files" folders, else you'll run into issues when there are configuration file changes. Windows will "protect" you from yourself there, and rollback any changes it does not handle directly.
Do you have your crew stuck at Battle Stations? Have you been "shelling-out" to Windows, by use of the <Windows> key combinations, or by use of the <Alt><Tab> or <Ctrl><Tab> key combinations? That will cause all sorts of weird issues. Also, the game is particular about the video settings, as attested by succerpunch's experience. Your display monitor has a 'native' resolution. If you look in your Windows "Screen Resolution" settings (or whatever they happen to call it in your version of Windows), you'll see a setting that has " (recommended)" next to the resolution setting. That is the one you want to set Windows to, and then go into the game, main menu, and choose "Options", "Graphic Settings". In the upper left, match the resolution in the drop-down box with what you have Windows set to. You have to exit the game to get it to "set", then come back in and see what happens.
You can also try changing the dpi setting in Windows. Find the SH4.exe file in the game's root folder, right-click on it, then choose "Properties" from that context menu with a left-click. On the "Compatibility" tab, click on the "Disable display scaling on high DPI setting" if you're in Windows 7, and "Change display DPI setting" (or something like that) in Windows 10. You want it to be program controlled. While on that "Properties" page, you could also check the "Run as administrator" and if still having issues, either use the Compatibility Troubleshooter, or set it yourself to Windows 7 or maybe even all the way down to Windows XP. You usually won't have to go below Windows Vista.
Whatever you do next though, do one thing at a time, and "test". If it takes three hours for each "test", all the better
- just have fun with it.
