07 Macbook pro 17" won't boot

Hey guys, I have a 07 Macbook Pro 17". its been working perfectly untill last night. I had it off the charger using it for an hour or so. Then closed the lid and went to bed.

When I went to start it this morning i noticed the battery was dead so i plugged it into its charger and left it for several hours.

I then went to start it by pressing the power button and found:

-No start up chime

-No keyboard lights

-No Display at all (just black with not even any back-light)

-Can hear Disk drive noise (although there is not disk in there)

-The front "sleep" LED is illuminated

-No response from any keys on keyboard

The battery is definitely fully charged. I have removed battery and unplugged wall charger for 30 seconds then tried to fire macbook up, NO CHANGE. Then removed battery and unplugged wall charger, then held power button for 10 seconds. NO CHANGE.

Tried resetting SMC following Apple support procedure, NO CHANGE.

I read a thread about one not booting and someone held shift, option, control and the power button down simultaneously for 5 seconds, this did nothing. Then when that didn't work they tried "Press power button,and immediately hold down the command, option, p and r keys simultaneously until you hear the start up chime" This also did nothing.

So my question is, What else can i try?