eM Client won't start or close down

I have just installed Em Client, sometimes it will launch, but when I close it down via the red cross, there will be a opaque “close” hanging in the top right of the screen, and the program won’t restart, so then I restart the laptop and i get the message box, em client database check, because it says it wasn’t closed down correctly, and I have to wait whilst it checks. Can you help?