Dell D630 screen not displaying upon boot?

I have a Dell D630 and when I boot up I only see a dark screen. It fully boots because I can hear the CPU as well as the Windows chime, Skype and a few other applications. After re-booting a few times, the PC starts up just fine and is visible on the screen. It may have something to do with the laptop thinking it’s top is closed so the screen isn’t showing. Please help. Thanks.