I used the phone yesterday with no problem. Upon hanging up, the keypad froze and the phone key guard has been on. I cannot unlock the key guard and use the phone. The on/off button does work in the sense that it will make the screen light up, but i do not have success enabling the key guard using "spacebar" + "back". I have tried removing the battery from the device but the keypad is still locked. The time and date are still accurate, so it appears the phone is receiving data from the network. Does anyone have any advice? Has anyone encountered this before?