Have you checked the monitor's connection to the system? Does Post come up? Is there any start up or splash screen?
Does it just always stay black?
I have a sony vaio desktop. When i turn it on, the light that indicates that data is being processed goes on for less than a second. the light that indicates a cd is being read also goes on for about 10 seconds and then stops. there is no clicking noise, although there used to be, and all of the panel lights are on, but nothing is happening. The monitor light is yellow, so no information is even being sent there. Any ideas? i don't think it is the hard drive because even though there was a clicking noise, i unplugged the hard drive earlier and the clicking noise persisted, even though, as i said, now it has gone away.