When did this start happening? Have you dropped it recently or installed any new drivers?
Can you see the boot window or the windows loading screen.
If it stays black throughout the whole process after pressing the on button until you hear the windows welcome sound then;
Could be a majority of reasons really, the ribbon cable for the monitor located by the hinges inside the casing has become worn and contacts are broken.
The monitor cable has become unlatched from the motherboard.
The screen is fried.
If you feel comfortable about it; Following the first few steps on this guide (direct from DELL) will enable you to open the casing and by reading the guide, check that the cables it tells you to unplug are in fact plugged in correctly:
When did this start happening? Have you dropped it recently or installed any new drivers?
Can you see the boot window or the windows loading screen.
If it stays black throughout the whole process after pressing the on button until you hear the windows welcome sound then;
Could be a majority of reasons really, the ribbon cable for the monitor located by the hinges inside the casing has become worn and contacts are broken.
The monitor cable has become unlatched from the motherboard.
The screen is fried.
If you feel comfortable about it; Following the first few steps on this guide (direct from DELL) will enable you to open the casing and by reading the guide, check that the cables it tells you to unplug are in fact plugged in correctly:
http://support.dell.com/support/edocs/systems/ins1525/en/SM/display.htm#wp1180071
James.