My screen is just black with power light on

Hello
I have fujitsu seimens.last time I did system maintenance on c drive n surf internet n switched off n went to sleep.
Nxt morning I wake up and tried to turn on but just black screen shows up.
Just power is on with capslock. N number lock light on.the cd rom works fine.
I friend checked if its got to do with ram or memory but nothing.
I dont know whats wrong.
Btw the laptop is 3 years. Old n imy memory was not that loaded as well.
Please help me somebody.
I would really really appreciate.
Thankyou