Need a bit more info, like where did you install SH4? What kind of computer, like what kind of cpu, what kind of video card? What's your screen resolution? When you installed, did you install the DirectX v9.0c and the Windows Media Codecs? Have you activated any mod? From the sounds of things, you get the menu, but what are you choosing after that? Like a career, Quick mission or Quick patrol? If you hit your Windows key when the game is stuck, do you see a dialog box in the Task Bar? Can you press the Esc key and go back to the main menu? Does The Museum work (takes a while to load)? "Need more data"... :O: :salute:

I was going to ask a couple of Props questions. My thought was RAM and CPU. I too had steam info that game is already running. I solved that by running and installing the game cd, ignoring SH4 on steam, (got a refund).

Windows 10
 

Get your money back from Steam and buy the CD on Amazon. Ubisoft has FAR to many problems with their Digital Rights Management system (and Steams)
I have the CD's and installed in Windows 10 any it works fine. MY problem is I also with the 1.5 U-Boat addon I PURCHASED from Ubisoft. When I installed it, the game won't boot. I can't activate it with the activation code they sent me.
I have ten emails with tech support and there last one was they wanted a picture of the original CD. They have done NOTHING to solve the problem.

The point of this is stick with the CD and if you can't install it and boot the game - return it as defective to wherever you bought it. You will get no help from Ubi.

The next ubisoft game will be called SuperBugs - par for their course

:har: unfortunately, they all do it. I don't think I've seen a game ever that came out that didn't have "bugs", some to the point to where you couldn't even play the game. Unfortunately ~all~ the software companies, including "modern" OS writers are the same, seemingly using the users as beta testers, or guinea pigs... reminds me of when I was in a band, and you'd record, and one of the guys that had made a mistake in their part would say "they'll fix it in the mix"... back then, the easiest way to "fix it in the mix" was to erase the part and do it again... Silent Hunter 4 is a rare beast in that they eventually got close, so long as you remember it has limitations. :salute:

I have suffered a boarding by Windows 10 OS upgrade
 

A recent windows 10 upgrade leaves me on the beach. Game will not open. Nada. I suppose I have to reinstall unless someone can share a hack. If I do have to reinstall- does everything need to be reinstalled?:arrgh!:

Do you see the opening screen when you start the game, and then nothing but "black", or is there nothing and it holds? or do you see a "flash" of an attempt at starting, and then back to the desktop? Depending upon where you are in the Windows 10 update process, and if you have an nVidia display card, it might be that the display driver will need to be rolled-back. Refer to THEBERBSTER's GPU Driver Roll Back To A Previous Version if your symptoms match that. Otherwise, in one of my SH4 copies on my Win10 laptop, trying to start the game would get me a "flash", and then go right back to the desktop. I had to de-activate all of the mods (FotRSU and mod work files), emptied the Save folder (C:\Users \UserName \Documents \SH4) and re-activated the mods. I had to re-set my game's screen resolution and other preferred settings, but it started back up just fine afterwards. Other copies, I had no issue, which I do not understand. Just make certain your Windows desktop display settings match the "recommended", which is your LCD display's "Native" resolution, and that you have the game set the same in the Options menu. You might also find that Windows has changed some of your file associations, especially for older "legacy" applications. Very frustrating. :salute:

it may have been the upgrade that screwed me up, for a while. There is a thread in here on compatibility and DPI settings. Resetting DPI got mine going.