iPhone doesn't start

[Andriex]

Hello. My iphone doesn't start. If i connect it to my pc-<<usb device not recognised>>. I can't do anything whith it.
Before this it had a white screen. I read somewhere that you fix that problem with a restore. i tried to restore it but itunes gave an error. then i clicked of on the error message and itunes stopped doing anything. i disconnected my iphone and after that i couldn't do anything with it.
Please help me.

 

[Applejuiced]

Try a dfu restore.
If still nothing might be a hardware problem.