First question as silly as this may sound but what color is the little light on the front of your monitor. If it is orange then it is not getting a signal from the computer. Check your monitor cable. If the light is green and there is no picture after the bios screen then there is a good chance of there being a problem with your drivers or video card.
If it is green and there is no picture as all then i would say your monitor has a problem.
If there is no light then you need to check your power cable.