Why is my Iphone 4 screen not working? - 1

I bought an iphone 4 from a friend and the phone worked fine. I updated the phone to IOS6 and then I started having all these problems with the phone. Certain spots on the screen won't respond when you click on it. Now the whole screen won't respond. I took it to the apple store and they didn't know what was wrong with it and wouldn't help me because apparently my friend got the screen replaced and she didn't do it with apple. Can anyone help me? Can I just get the screen replaced would that fix it?

Added (1). I have already restored it and set it up as a new iphone multiple times and I have also tried resetting it by holding the home button and lock button and none of that works.

Am I Being Scammed By Selling My iPhone?

So i'm in the middle of arranging to meet somebody off the internet to sell them my iphone. I have told the person I will meet them at a local cafe and they can of course play on the phone etc before they decide to purchase it from me, so to make sure that they are satisfied. HOWEVER, this person is asking me to bring ID with me for them to take a copy of when I meet them? THIS SEEMS VERY STRANGE TO ME. Why would they need this? I really do not feel comfortable giving my details to a stranger. Is this normal for somebody to ask for when buying off the internet, or am I right to be a bit weary?

How to permanently delete a contact from my iPhone 4s?

Its more than just selecting the contact and hitting delete. When I do that, if I create a new text msg the contact is still there.
For example… Contact "Laura" is deleted, I create a new msg and type "L" in the To: field and Laura is still there. (the number, and not the name shows up after selected)
I have even went into my iCloud but that made no difference either

Added (1). It didn't occur until I updated to ios 6

How to Keep iPhone Lock Screen ON (keep it from Dimming / Blanking / Going to Sleep)?

I'm having a jailbroken iPhone 4S, running iOS5. What I would like it to do is to keep the "lock screen" (the one with the clock and the slider, not the homescreen) ON for ever, if connected to a cable. I have a neat stand for my iPhone next to my computer, and would like to use the iPhone as a clock (but without having to start a specific app, it should happen automatically).

How can I get this to work?

Thank you for any help!

Btw. I did some web research, of course, but could not find a solution. (1) I tried "nolock" (on Cydia) does not work on iOS5, (2) "lock screen dim delay" only delays by 30 min, (3) disabling auto-lock in setting prevents the lock screen from coming up, it does not keep the lock screen on