it seems that we has the same issue.
did you already tried to install the driver of your internet adapter (to check go to my computer right click then properties hit hardware tab choose device manager and look to the name of your network adapter e.g Ethernet Rhine II)
check also if your network configuration is not configure properly
click start>run type ncpa.cpl (enter) right click the local area connection properties click internet protocol (tcp/ip) click properties button and hit obtain ip option button and obtain dns click ok ok then restart
restart your local area connection to do this click start>run type ncpa.cpl (enter)
right click local area connection choose disabled then right click again and choose enabled.
also contact your internet service provider maybe your internet connection is currently down.
check the light of your modem. (light depends of the modem model)