If a sudden jar, however so light, causes the display to fail, or come on, there is a loose connection. It could be in the power supply, the video driver, or a cable/wiring. Unless you are competent in troubleshooting using a wiring diagram and a digital meter, it's best to either replace the monitor or take it to a qualified electronics repair shop. If you do the latter you can probably buy a new monitor for the cost of repairs. Since LCD monitors are more computer than video device, I'd recommend replacing it.