Mfc100u. dll is often found in Windows system folder (-System32- / -SysWOW64-), but can also be found in the install directory of a program using the file.
vc_redist.x64.exe is what you want if your using windows 10 or windows 7 64bit. Install it and reboot the computer and then try launching your game again.
Download the Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package MFC Security Update and run it. This will replace/restore the mfc100u.dll with ...