Blank screen on my Inspiron 1525

Hello,Everyone sorry 4 interrupting,

I have a problem with my Dell Inspiron 1525 (Vista Home Premium)
I bought it on 2008 and till now im still using it..But last week i have encountered problems while starting it and now the screen appears blank after i press the on button..The light which shows up in my laptop is the power light and the Hard-disk 's light shows up 1sec after i press the on button....My question is

-Is there any hardware problems that need to be changed ....
-My hd is full ,so is it the problm...

Pls help me to over come this problm ...appreciate it to all ....