It hasn't worked since September. I have tried everything, but it won't work.
My iPhone has slowed down. What is wrong?
Faulty construction, virus, software errors… Could be any number of things. The solution is to see if you can upgrade to a sparkly new Android phone or wait until Windows Phone 8 comes out and get a phone with the OS that holds the record for highest customer satisfaction.
Android and Windows Phone > iPhone
Not sure what you mean by slowing down, but I would recommend updating / restoring it. Jailbreaking it can also slow it down tremendously.