Does it act like its trying to boot up. Also, if you are using an LCD monitor sometimes you have to turn them off and back on again. My Samsung is like that when I change cards out and such.
Also, check bios for video display settings if you are using an onboard video pot.
Thank you RandyW for the reply.
When I Switch On my Pc smps, Processor's Fans Starts and Keyboard LED glows for a second and then blank screen nothing happens.
Even unable to see the BIOS Configuration.