Hi there. I have two computers where one of them is notebook computer and the other is desktop. Between desktop and server, no problems at all. I can ping it's IP as domain name. On the notebook, there is no chance to receive any ping reply with domain name. What is causing this? That's probably the reason why sharing doesn't work on laptop.
I don't know why, if everything is being configured on the same way on both interfaces. Here is what you can try. There is one file inside \windows\i386 directory called hosts. This is used for fixed IP and domain names mapping. Open with notepad, and according to the instruction given there, you can set things straight.