Screen does not display, pc not booting

While working on my pc yesterday, the screen suddenly went black and there was no signal being fed to the the screen and then the screen keeps turning off. I thought it was a graphic card prblem and changed it but it still does not display. The fans on the graphic card are not spinning, so probbably its now a motherborad problem. To add to this,the computer still turns on but there is no ‘beep’ to say that it is booting up. Please can anyone help as I need this pc up and running as soon as possible!. Thank you for your help!