How to fix an Iphone 3G stuck on lock screen with loading circle?

My phone was perfectly fine. I was on the phone with someone like 3 minutes maybe less before it messed up. Now it's stuck on the lock screen with a loading circle spinning. Some one please Help!

Try waiting for it to die. It might take a while, especially if it was fully charged. After that, try charging it. If that still doesn't work try redrafting your iPhone by holding down the power button until a red arrow comes up and says 'Slide to power off.' It should make the loading circle, then look like it's dead.hold the power button down again and the Apple symbol will pop up. Then just wait a dew minutes and it should be good to go.