Why my laptop doesn't start? The led remain even off...

Two weeks after the end of the guarantee, my laptop refused to start (while I was using it normally few hours before)

Refuse to start means : nothing... really nothing... not even the power leds.

I tried of course to press the power button a while to empty the electricity...

noting..,

I have disassembled the laptop, I have removed the battery and CMOS battery. And, when I plug the cable, I see one led flashing once very fast

HELP!!!!