Booting problem with PC

Hi, i am new member. I have problem with my PC. While working on my computer my computer screen suddenly changed to black screen and some warning is display i.e drive not readable please ctrl+Alt+del for restart
when i did ctrl+Alt+del to restart it won’t boot only and again display the same thing with black screen.

So basically my problem is my machine is not booting only. I checked the power connection of my screen also turn off the main power connection of my computer but it won’t work for me.

SO PLEASE ANYBODY CAN HELP ME IT WOULD BE OF GREAT HELP.

Check the drive & connections.