Boot up problem

Hi all,

My Hp compaq presario cq61 330sa laptop won't boot up.

I was using it this morning when suddenly the screen turned white and froze.

So I reset it and now it won't boot up. The power button comes on, the fan turns on, and the caps lick and num lock blink in a sequence of 1 blink per couple of seconds, and the screen remains off.

How do I get it to boot up? And how do I fix this from happening again?

Please help if you can..

Many thanks!