Fix :- iPhone rebooting or stuck on Apple / iTunes Logo - How To DFU Mode
1. Make sure your iTunes is updated to the newest Version.
If your iPhone was Jailbroken, you WILL have to use DFU mode to update to iOS 8 (or to reinstall 7.1.2 if you have an iPhone 4).
DFU mode helps when your iPhone won't restore or is stuck on Apple Logo or itunes Logo, or if you want to jailbreak your device.
Works on: Windows XP, Vista, Windows 7, Windows 8
Works with:
iPhone 3G 3GS 4 4S 5, 5S, 5C
iPad, iPad 2, New iPad 3, iPad Mini
iPod Touch 1st 2nd 3rd 4th 5th Generation
2. If for some reason you do something wrong, and the "phone won't switch on" anymore, meaning the screen stays black. Just hold both the home and power button for about 20 seconds. The phone should switch on again.
To solve Error 3194 on Windows:
1) Update iTunes to the newest version!
2) Go to the following folder:
C:\Windows\System 32\Drivers\etc\
Delete the hosts file in there (if you have any illegal programs on your PC, you have to edit this file - don't delete it)
Close and reopen iTunes. Now error 3194 should be resolved.