iPhone 4 wont charge via usb

Hey!

Yesterday I left my iPhone 4 at almost no battery life at all charging on my laptop which also ran out of battery since it was not corded. When I got back home my iPhone 4 would respond to anything, it wont work with DFU-mode or pressing home button while putting the usb cord to the laptop. But it worked when I used the wall adapter but it stays on the thin red bit on the battery display and wont charge. While it does that it says i need to restore my iPhone but cant since my computer wont recognize it. I've tried to connect my iPhone 4 to different computers and it does not give a sign. Also looked on the guides on apple.com to uninstall Itunes and remove everything that belongs to it. Reinstalled it again but nothing happends. Is my phone bricked? It's the first time im loading it from scratch, only got this phone for 3 days. What should I do? Now im got my iphone 4 corded to the laptop and let it be there for 1 day otherwise i return it to the store.

Sry for my english, not my primarly language.

Thanks in advance.