When i make or receive calls, the screen seems to go blank. I can hang up by pressing the power button, but after doing so i have to wait about a minute before i can use the phone again, as the screen seems to freeze in 'off' mode. It's also a problem when i make calls that require pressing a key - (like the O2 helpline!!) as i can't press '2' or any other key to speak to anyone on the helpdesk! does anyone know what i should do about this? Or is anyone else having the same problems?