Compaq Presario CQ56 not booting, not even to BIOS

Hi

I have a 3 years old Compaq Presario CQ56. Recently I was using it and the screen blacked out and the only thing I could was shut it down. When trying to boot it up again, I could hear the fan going, but nothing shows up on the screen, there is no sign of hard drive activity, it is as is it doesn't even get to the BIOS. I need to force it to shut down by pressing the power button or by removing the current. This started a week ago and resting the computer did not help. The laptop is not running on the battery. The DVD drive can be opened and closed.

What I have tried/noticed so far:
-the white Caps lock light is on (NOT flashing) as well as the wifi red light.
-I did the "hold the power button down for 30 seconds tricked while the computer is unplugged" and it didn't change anything.
-I've removed the current RAM and tried new ram (same make and model) in either slots
-I've dismounted the whole thing and removed the CMOS battery for over 5 minutes to reset it.
-I've also booted the computer without the hard drive attached.
-The computer did not show any signs of imminent failure (no fan working hard because of overheating, no slowing down, the clock showed the correct time, etc).

So I am thinking that either the motherboard/processor/onboard graphic card is dead and that I shouldn't bother anymore with this laptop which costs less than 300$ 3 years ago. If I understand correctly, the lack of caps lock blinking means that it doesn't even get to POST.

What do you guys think? Anything else I could try?

Thanks

Max