I'm having this problem for almost a week now. I've always been a Nokia fan and this is really the worst phone that i ever had. I thought doing a reset of the phone's settings and reformatting the memory card would fix the problem but it didn't. I don't want to go to Nokia and leave my phone for several days but for those who already did, how long did it take before you had it replaced and did they ask you to pay for it's replacement?
Well it is the touch screen phone and may be it has something with the internal sensors of the screen. Sometimes due to over press the screen it happens and the screen could be damage. There is no connection of formatting the phone and the screen it will only reconfigure the phone in its default mode and configuring and nothing but with that you might lose your contact and other important files in phone memory. Well as the actual problem has not been mentioned by you so I can not give you the proper suggestion but it is the best to show it to your nearest Nokia Authorised center.
It is very simple, you slide the phone has two small screws to remove and when you slide away, has two small screws to unscrew. Upon receipt of your screen there will be a small screwdriver to unscrew it is very easy when it was decided to screen with a blue plastic (also included), then you removed and replaced by his new view. Attention should not be forced to terminate the small orange that connects to your phone screen when you are replacing. A board should return the top of the screen before putting it in place.