u did'nt specify ur problem properly....what exactly happnened to ur LAN or internet.....there r many reasons behind it .....some of them which i know r trying to specifying to uuuu.........

first there may be the possiblility u disable ur LAN icon.......to make it enable..start->settings->network and dialup connections.....or u can do one thing more start->settings->control panel->here u too find network and dial-up connection.........from here u can make ur LAN enable........second possiblility that there may be malfunctioning in ur LAN card....may be driver could be currupt..........