What is the problem with my latitude D400?

Hi guys... I was shifting my d400 from one table to another. So, i had removed the power cable from the laptop to make the moving easy and safe. Both the laptop and the power charger were still on. After shifting the d400, I plugged in the power to the laptop as I often used to do ...

To my surprise, I saw the screen go black and everything off suddenly on the laptop!

I have been trying to switch on the laptop several times now, the normal way but nothing has happened...

Can anyone please advise as to what might have gone wrong? is the motherboard ok? any memory problem?please help..... All my work are in the hard drive!

Thanks...