HTC INCREDIBLE S PHONE !

hello i have a htc incredible s for sale this phone is in good condition there are no marks on the screen it is on android 2.3 and has htc sense 3.0 installed it is unlocked to all networks there is a slight problem though the phone will turn on but after a wile it will shut itself down this happens at different times it could shut itself down on the boot screen or shut itself down after 5 hours or so i think it might be the battery or a hardware fault or it could be something else i dont really know much about phones although when it does power up to the home screen the phone is great to use the phone comes with the charger a usb cable the battery and a new case i am open to offers if you have any questions please ask i am able to give a quick reply by email or by phone thanks calum