Inspiron 1520 startup problem

Hello everyone,

I have a Dell Inspiron 1520 and from 4 days I have a startup problem.

When I turn on the Loptop the blue leds turn on but the screen remain black.

I tried reset the motherboard and the RAM but nothing good results.

I have two short beep cod, but I don't know the meaning.

What is the meaning of the two short beeps?

Thanks in advance.