I have an HP G60 230 ca...very similar problem....black screen on turn on...leds come on and stay on , no blinking , no beeps...
It does scroll through a cd if I put one in but not open it...I beleive i can hear either the processor or fan running it's very quiet.
Took it to a tech shop a while back and he "thought " it was probably one or both ram sticks...was going to buy some but not sure that is the issue...
someone on an online forum thought it was the motherboard and i wonder if it can even be the screen....did the same tests as the other guy but to no avail.
thanks for your help.