De-Authorizing my iphone from previous computers?

Hi, i brought a book for my phone today, but i can't put it on it due to my itunes account being authorized to 5 previous computers. These computers i no longer own, is there another way of getting it onto my phone?

Iphone 4 stuck on Apple Logo. Read Description?

It's already been Jailbroken for some months now. I was trying to reboot it and now it is stuck on the Apple Logo. It won't connect to Itunes either. When trying to hard reboot it it showed the battery icon that showed it needed to be charged But when i plugged it up it and let it sit for about 30 minutes it was still on the apple logo. Anyone know what to do?

Added (1). It WON't connect to Itunes

Straight talk Iphone 3gs running 4.1 won't send mms pics?

I have tried everything I can find, and my Iphone 3gs 32gb running 4.1 won't send mms pics. I initially tried straight talks fix, didn't work. My phone is jailbroken. I then installed tether me, and Swirlymms2, and still the phone won't send pics. Can anyone give me a fix for this?

Iphone won't turn on while charging?

My iphone battery died completely and i put it on charge. Now it is just on the charging screen and has been for about half and hour but won't turn on

Where to bring my broken iPhone?

My camera is broken on my iPhone 4s. Everything thing else works. I've had it since July. But I have Verizon and I don't know whether to bring it to Verizon or the apple store to get it fixed? Will apple fix it for free? Because the camera just stopped working, I didn't drop it or anything.

Why won't my iphone 4 connect using 3G?

I have just got an iphone 4, it is second hand but was in perfect working order. I can't get it to connect to the internet using 3G it will only connect using Wi-Fi. I have tried every setting vodafone have told me even trying a new sim card but it still won't work.
Vodafone have now decided the phone must be faulty but I'm not so sure.
Does anyone have any suggestions?

Why isn't my new iphone 4s sending messages?

I have had my iphone for about 2 and a half weeks and ever since i bought it it hasn't sent messages right… I have tried to reset it and i looked at imessage and made sure everything was right on that and it still won't send messages half the time… Plus i can't get incoming calls sometimes i will have to call the person thats trying to call me… Should i take it back to c spire or what?