We'll need more information about your computer such as the operating system, make and model of the computer, age of the computer and any error messages you may have seen before or during the problem..
If the computer is a desktop computer, have you tried simply swapping in a known "good" monitor? Maybe borrow one for a test? Tried swapping in a different power supply?
Hope this helps and let us know more.
when I turn my computer on it powers up and the fans work, but im not getting anything from my cd rom and I can't hear my hard drive.. My monitor reads no signal.. Does anybody have an answer fo0r me