|You haven't supplied enough information.|
The more info about your symptoms you supply, the more you tell us about what went on before this happened (e.g. did you install Windows from a regular CD recently? Did you install video drivers recently? ) the more likely we can find a solution for you.
A computer that is producing no video doesn't necssarily indicate there's anything wrong with the monitor or the video adapter it's plugged into.
Try the monitor with another computer. There's probably nothing wrong with it.
State the make and model of your brand name system, or if it is a generic system, the make and model of the desktop mboard.
The specific brand name system model is usually on a label on the outside of thecase somewhere, or it can be determined by going to the brand name's web site.
The model of the mboard in a generic system is usually printed in obvious larger characters on the surface of the mboard, often between the card slots.