I can't browse the Internet, but it says I am connected. All I get is "Page cannot be displayed".

Most home networks today will consist of a broadband modem/router and one or more computers that share that Internet connection. The router has two IP addresses: An exterior IP address seen by the outside world and an interior IP address seen only by the computers on the local network. Your ISP assigns the router it's exterior address, which may be something like 154.X.X.X (where the Xs are numbers).

The router will then give each internal PC its own local address, usually something like Other PCs will have an address similar to, etc. In this case the router is considered the DHCP server and the gateway to the Internet. When you boot your machine, the computer will broadcast a request for an IP address and the router will normally answer. If it does not see the DHCP server, it will give up and make up an IP address for itself which will often look something like 169.X.X.X. This is a local address that will not likely have any communication with other PCs on the network. This network connection is often characterized as having "Limited or no connectivity".

We mention the 169 IP address because people will suddenly lose Internet connectivity when it worked the previous day. An easy way to attempt to fix this is to just reboot everything—modem, router and PCs.

First, check to see what your IP address is.

Press Windows key + R to open a Run dialog.
Type CMD and press Enter
At the command prompt in the DOS window, type IPCONFIG /ALL and press Enter.
The result should be something like this:

Ethernet adapter Local Area Connection:
  Connection-specific DNS Suffix:
  Link-local IPv6 Address . . . . . :
  IPv4 Address. . . . . . . . . . . : 192.168.X.X
  Subnet Mask . . . . . . . . . . . :
  Default Gateway . . . . . . . . . : 192.168.Y.Y

You will be able to see a lot of information about the Default Gateway and the IP address of the computer. The IP address should be similar to the RED numbers above.

If you do not have an IP address at all...

check all your physical cables and wires to and from your system, the modem/router, and the the wall outlets. Make sure your Ethernet drivers are installed and the device is enabled by checking the Windows Device Manager under Network Adapters. You may need to contact your Internet provider if this problem persists.

If you have the 169.X.X.X IP address, try the following:

Shut down your PC
Unplug the modem/router. Wait a two minutes
Plug the modem/router back in and wait until all lights are green
Reboot the PC, wait a few minutes for a new IP address to be acquired, and test

Even if you have the correct IP addresses, it's not a bad idea to reboot everything occasionally. So if your Internet speeds are slow on all connections, or if you suffer from a loss of Internet connectivity, reboot the modem, router and PC for a quick fix.

If you have an IP address similar to the RED numbers above, but still cannot browse the web, try the following:

For Vista or XP SP2:
Press Windows key + R to open a Run dialog
Type CMD and press Enter
At the command prompt in the DOS window, type NETSH WINSOCK RESET CATALOG and press Enter
Next type NETSH INT IP RESET RESETLOG.TXT and press Enter
Restart your computer and test

For XP:
Download and use the XP Winsock fix which resets the winsock networking component within XP. Helpful instructions are found here.