Computer turns on and nothing happens.

Hi,

Last week my computer suddenly stopped responding. I turned on the sleep mode, went to bed, and when I woke up it didn't work. I think there was a power outage at night because all my other devices were turned off.

When I turn it on, all the lights and fans are working, even my keyboard turns on, but that's all. There's nothing on the screen and no beeps. I disconnected all additional cards and everything, cleared CMOS etc. I'm now out of ideas.

So are there any suggestions?