You should also check your network device is working properly.
1) Go into the Windows control panel and select Performance and Maintenance
2) Then select "See Basic Information about your computer". This will open the System Properties window
3) Select the Hardware tab, then press the Device Manager button. This shows the Device Manager window.
4) Have a look at your Network Adapters entry. Click the plus sign to show the device
5) RIGHT click on the device and select Properties to see the properties of the device. It should say "This device is working properly"
If there is a problem you may see a yellow question mark against the device in error. See this picture for an example of the yellow question mark.
http://www.infopackets.com/graphics/device+man ager.gif
If there is a question mark you need to correct the error. This may be as simple as re-installing the drivers.
You can also use the Troubleshooter button to try to solve the problem.
If you have more than one network device, make sure the correct one is being used.
You can also see your network connection details in the Network Connections window I mentioned in an earlier append.
Make sure it says "Conected". If not you have a problem.