about 1 year ago - AndrewT - Direct link
Has it ever worked on this machine? Or never yet?

If you run eu4.exe directly from File Explorer does it start that way? If not do you see a Windows error?  
about 1 year ago - AndrewT - Direct link
That Windows error means a bad or missing Microsoft DLL.

First please try this Windows repair tool

Use the System File Checker tool to repair missing or corrupted system files - Microsoft Support

Describes how to use the System File Checker tool to troubleshoot missing or corrupted system files in Windows 8.1, Windows 8, Windows 7 or Windows Vista. support.microsoft.com support.microsoft.com

If that doesn't help, Install ALL these Microsoft modules:

Download Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package MFC Security Update from Official Microsoft Download Center

www.microsoft.com www.microsoft.com And run the x86 and x64 installers there.

Download Microsoft Visual C++ 2015 Redistributable Update 3 RC from Official Microsoft Download Center

www.microsoft.com www.microsoft.com And run the x86 and x64 installers there.

support.microsoft.com

Latest supported Visual C++ Redistributable downloads

This article lists the download links for the latest versions of Visual C++ Redistributable packages. support.microsoft.com And run the x86 and x64 installers there.

Download DirectX End-User Runtimes (June 2010) from Official Microsoft Download Center

www.microsoft.com www.microsoft.com (run dxsetup.exe after extracting this download to its own folder anywhere on your computer)


Good luck!