iPhone shows charging screen but its not charging

Hi,
I have following problem. Few days ago, i changed battery in my iPhone 3G. But i have problem with new battery and now even with the old battery. The iPhone is almost dead. Everytime i try to turn on, it shows only charging screen. Even if I connect it to my laptop or to electricity. I don't know where is the problem, I tried restore but it didn't helped too. I even bought a new one battery, but without result.
Please help me, I'm really desperate. Where is the problem?
Thanks a lot.
PS: Excuse me for my bad english, I come from Czech Republic.

batting1000 said:

There's your issue. You should have had Apple replace it.

Click to expand...

In my country, there are no Apple stores or something like this

But I've already solved my problem