How come my iphone hangs up?

After I talk on the phone for exactly 30 minutes it hangs up and it's starting to annoy me. It is an Iphone 4 btw. Can you guys please help me?
PS I have it lock after minutes if it helps.

Open up an iPhone application, it just freezes and hangs there. You probably try to press and hold the POWER button to turn off the iPhone, but it doesn't respond.

This is not uncommon for you to encounter the above hang problem as you install more iPhone applications. A friend of mine, who have bought the iPhone 3G for around 2 weeks, gave me a call and asked for resolution.

So, what can you do to resolve this problem and bring your iPhone back to normal? For experienced iPhone user, you may know what to know. But for iPhone beginner, this hang may scare you.

Don't worry. The solution is trivial and simple. What you have to do is to do a Hard Reset on the iPhone. To reset the iPhone, simply press the POWER/SLEEP button and Home button together. Hold them until you can see the boot screen, which is with black background and Apple logo. One point to note is you have to release both buttons at the same time.

  • Will the iPhone 5 lose it warranty when the iPhone 5s and 5c come out? I know that my sister's friend bought a iPhone 4 about a 6 months ago and she found out the hard that they are no longer under warranty, for if something goes wrong. I currently do not own a smart phone and was thinks of getting a iPhone 5 since the prices will be cheaper now. My fear is that since it is cheaper they will not give a warranty. So does anyone know the deal with Apple and whether they are going to contine covering the iPhone 5 under their warranty?
  • Will the Iphone 5 get any cheaper now that the Iphone 5s and 5c Have come out? I'm looking to purchase an iphone 5 outright, new and they now do not sell it on the apple website. I have seen it on other websites and i wanted to know if it will go down from its price at the moment ($788) or will stay the same?
  • Why does my iphone 4S hangs up calls if I lock the screen? I have noticed my iphone 4s hangs up calls if screen is locked and the thing is it does it pretty randomly. So sometimes it hangs up while other times it won't. Today I made a call and locked the screen and nothing happened so the call was maintained but a few minutes ago, I received a call but locking the screen ended the call. So I called the person back and tried again, the call was ended again. Does anyone know what the problem is? Any help is appreciated.
  • When i plug in to ethernet my computer hangs? Dear Sir i have problem with my ethernet, actually i used a software to how broadcast internet for iphone after sometime i faced with this problem now when i plug cable laptop hangs until unless i switched off and restart computer, please give me solution for this.