This function retrieves the handle to the top-level window whose class name and window name match the specified strings. This function does not search child windows.
HWND FindWindow( LPCTSTR lpClassName, LPCTSTR lpWindowName );
[in] Long pointer to a null-terminated string that specifies the class name or is an atom that identifies the class-name string. If this parameter is an atom, it must be an atom returned from RegisterClass. The atom, a 16-bit value, must be placed in the low-order word of lpClassName; the high-order word must be zero.
If this parameter is NULL, it finds any window whose title matches the lpWindowName parameter.
[in] Long pointer to a null-terminated string that specifies the window name (the window's title). .
A handle to the window that has the specified class name and window name indicates success. NULL indicates failure. To get extended error information, call GetLastError.