You could try:

1) Reseat the user-accessible RAM module.

2) Remove the user-accessible RAM module.  (There's another RAM module near the CPU, so removing the user-accessible one will still allow you to power the system up).

3)  If that doesn't work, then remove the keyboard, and remove the CPU heatshield, and check to see if the CPU got unseated somehow and reseat, replace or swap the internal RAM module (since you've got the keyboard and CPU heatsink shield removed)

Please make sure that you don't have the 10NRN media cable, an external monitor, usb devices or anything else attached before doing any of the above.

And just to clarify, are you getting any green LED lights to show on the laptop itself when you press the power button?  Does your battery test button show all green lights when you press it?

Thanks, I'll try to do that.

No, I don't have any LED to show on the laptop when I press the power button. There's
only the green light on the AC adapter which is lit. Regarding the battery test lights
(I didn't knew about these ones !), only three of them show (1st, 3rd and 5th) and
they blink.

Eric

The battery flashes (1,3,5) indicate that something is probably wrong with your battery, and it will most likely need to be replaced..  Just do a forum search for battery flash code to read up on this.  A dying or dead battery shouldn't prevent you from booting up your computer, but if none of my other suggestions helped, you can always try this:

1) Remove the battery and AC Adapter from the laptop
2) press and HOLD the power button down for 30-60 seconds (I've read here on the forums that this will discharge the motherboard)
3) insert the AC Adapter (leave the battery out) and press the power button

Will it boot now?

 

It boots !!!!!!!!!!!!!
Thanks a million....

Eric