All of sudden your PC crashes and it you force it to shut down and when you try to start it again your system  starts but there is nothing on your display unit. You may have no idea what will wrong with your system. If this problem exist for you then i will guess this problem will be because of the displaying unit. Here we list the possible tricks that may help to fix your problems. We advise you this trick may not work for all of you in such situation make sure to reach the service points.

* Check your monitor power supply and and display cable connections

* Check your disply cable connection on your system cpu

* If your system has a dedicated graphics, remove it

* Try plug your monitor on the onboard graphics, it will help to detect problems in graphics

* f the pc uses onboard graphics only, try plugging in a dedicated PCI/VGA graphics card and test if you can get images through that

If any of the above methods doesn't work for you then fix your computer by your own is an difficult task. I will recommend you to take it to the service points. They will figure out the cause for your problems and this will cost you too. Hope this information might be useful for you, Happy Computing !