By far the most common mistake people make is to forget to check the power cables! Sometimes, when monitors are moved around, the power connectors come off or become loose. Plug all cables in tight and check if the power returns. If it is connected to a UPS or stabiliser, check if there is power supply from that unit. Also check the power cable; try using another cable which you know works, to see if power is restored.
If the power cables are plugged in and there is still no power, the problem is more serious. It could mean that a fuse has blown, or there is a more serious problem with the CRT (Cathode Ray Tube).
Solution 2: If the fuse is accessible from the casing of the monitor, replace it and check. If the fuse blows again, or if it still doesn’t power up, you have a problem with the electrical circuitry inside the monitor. Your only option is to take it in for repairs.