Nokia :: 5800XM Screen Turns On For 30 Seconds And Then Turns Off

Over the last 3 days ive noticed my phone using a lot more battery than it usually does, i can usually get upto 2 days battery usage when its used frequently, but it has been getting less than a day over the last 3 days.

I turned the phone off with the power button and tried to turn it on again, The instant i press the power button the screen turns on (stays black but becomes a dark grey with the backlight) for about 30 seconds, but nothing else happens, the screen turns off after those 30 seconds and its back to square 1.I have tried turning it on again without a sim card, or memory card, or both and still the same result