My iPhone has slowed down. What is wrong?

It hasn't worked since September. I have tried everything, but it won't work.

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.