You can use the window classname instead of the window title. For instance, you can find Firefox with
HWND firefox = FindWindow(_T("MozillaWindowClass"), NULL);
You can use any window spy type application like WinSight, WinSpy++, or (the one I used to find the Firefox window class) AutoHotkey's Window Spy utility.
For more info, see the MSDN documentation for FindWindow
.