Apple 4 upgrade iOS7 after the screen can not be cut off how to do

1. For iphone4 mobile phones, we are not building your upgrade to the IOS7 system, after the upgrade because the configuration is too low (for IOS7) then we will encounter typing slow, slow response, the application play automatically back and so a series of problems, this is the Apple 4 of the memory is not enough.

2. The problem is also no way to use the computer to connect with the itunes and then delete all the applications on the phone, but also to restore the factory, but the return of the phone in the factory phone also text messages will be deleted OH.