This is what I've got. I cannot boot and I see the two of three little lights on the keyboard blinking all the time and the cooling is working on full power, almost.
I saw in other askubuntu topic suggestion for memory test. I did it. I didn't have any errors.
I am 99,9% sure it is not a hardware problem, because I have Windows 7 and I can boot it and it works just fine.
This problem came without any warning or something. I just turned off the laptop one day and at the other day I couldn't boot.