UBUNTU Ver.10.04 LAN NETWORK SETTING PROBLEM.

I started using UBUNTU OS Ver.10.04I started using UBUNTU OS Ver.10.04 a few days ago and I faced a problem that I am first time successful setting of my LAN network setting , but soon after using that setting gone bad but I tried again. And I failed to set this setting of Lane Network, why not work this again and I also restarted several times my pc but it does not work. Please reply in detail will be appreciated. Thanks.
