Did you purchase the game twice (once on Steam and once on Amazon)? I ask because I could not register my Amazon key with Steam and had to download from Amazon directly, so I'm curious how you downloaded from both locations? If you did buy it twice, is it installed twice?
If it is the Steam version, have you tried to disable the Steam overlay? If not, that may (or may not) help. Go to your Steam library, and right-click on the Ship Simulator Extremes listing on the left side, then choose 'Properties' from the pop-up menu. On the 'General' tab, make sure 'Enable Steam Community In-Game" is not checked.
If it's the Amazon version, have you tried possibly running it in compatibility mode for Windows XP SP3 and running it as Administrator? I can't say if that will or won't help, but it couldn't hurt to try (since the game requires XP SP2 for a minimum.) Best of luck, I really hope you get this worked out.
-George