Huawei 3G and Local Area Connection

[AGENT 001]

I have here a working Home Network containing my PC and Laptop connected through a Cross over cable. I usually connect to internet using Huawei 3G Datacard. When the Home Network is active (Local Area Connection connected), I can't access internet using Huawei 3G. It is getting connected, but not downloading any data. Ping test at that time is showing 100% Loss. When I try disconnecting the Ethernet cable, its working fine. Please help me, I want to use internet when I'm connected to Home network using Ethernet cable.

Thanks.

Problem Solved.
It was my mistake. When I configure the network, I set both the systems as client (This computer will connect to internet using residential gateway or another computer on my network). Now I re-configured it like this:
This computer connects to the internet directly or through a network hub. Other computer on my network also connects to internet directly or through a hub.