Steam version + Win10 = WTF

[propbeanie]

Try reading CapnScurvy's posts (and the others) in the thread Silent Hunter 4 & Windows 10, being sure to follow the link to his Windows10; Large Address Aware; SH4 Install thread. Also, if you read through THEBERBSTER's thread linked above, he's got several tips for Win10 users, as does CapnScurvy in his.

UAC in Win10 can cause issues, so try running As Administrator. Compatability Mode might be needed. Video drivers have caused trouble for some users, and you may have to roll your driver back (though the last case of that was nVidia). Also, if you haven't tried it yet, some systems need you to set your display resolutions to match. ie: Whatever the "native" resolution of the monitor is, set your Windows display driver to that, then match that in the game, if possible. If you're not getting to the game menu though, you should un-install the game, and delete the My Documents / SH4 folder, which holds Saved games and computer settings, and try re-installing...