iPhone screen is black and unresponsive to anything and power button is broken

Last night my iPhone 4while in the middle of texting went completely black and unresponsive. I put it on the dock charger for hours and it the screen went white with this border of grey color (almost like a picture frame) couple hours later it's back to being black. it will not connect to my computer and the power button has been broken for a while. I did not drop my phone or get water in it. I Don't know if iPhone is gsm or cdma (phone is Mts and off warranty)