How to fix my iphone 4 after ios7 update?

This morning I updated my iPhone 4 to the new IOS7. All day it wouldnt turn on and when I got home from school I plugged it in. It turned on and now, with it still on the charger, It keeps turning on for not even a minute, then the screen does something funky, and then it turns off. As soon as it's off The apple logo appears again, turning it back on, and then it continues to do the same on and off over and over. Its been doing it for about three hours now. I really need my phone to work… Has anyone expirienced this and happens to know what I can do to fix it? I've already called Apple support and they told me that they don't know what to tell me other than for me to schedule and appointment to take it to the apple store. Does anyone know what I can do to fix it without having to go to the Apple store?

Everybody and their brother is having problems with IOS7… Glad i waited… In about 6 months everything should be OK… My Droid is just fine no problems

I've just downloaded ios7 for my iphone 4 and the problem i have experienced is when adding a new contact it allows me to put in numerics but won't allow me to put in letters to spell the name, i have tried holding the relevant number to the letter, but nothing it just adds the number I pressed instead. I don't know how to change the numbers to letters i have tried quite a few times to no avail. I have tried editing and again no letters to use only numerics, getting quite annoyed with it now, does anyone know how to change them over when adding new contacts please.