iPhone 3Gs will not light up.

I went to bed and my phone was working but when I woke in the morning my iPhone screen will not light up. The screen is visable and I have been able to check the brightness settings which are at the highest settings, it is just not lighting up. I have reloaded my phone in iTunes and also tried the two button reset many times with it plugged into a power source.

Any suggestions would be great.