Sony Ericsson W910i turning off

Question

I have a sony ericsson W910i. it is 1 week old and i'm on a orange contract. the problem is that it turns itself off. the back red light (recording light) remains on and a slight side background screen light remains on but nothing on the screen. the only way to turn it on is by taking off the battery then putting it on again and rebooting. i have tried recharging it when this happens but still it will not turn on unless i take off the battery and reboot.