What do you do when your broadband connection stops working? Your first troubleshooting step should be the automatic Repair option available with all network connections.
Open the Network Connections folder from Control Panel, right-click the connection icon, and choose Repair from the shortcut menu. (Alternatively, you can double-click the connection icon, click the Support tab, and click the Repair button.)
Selecting this option has the same effect as typing the following commands from a command prompt:
- ipconfig /renew Automatically renews your IP address from a DHCP server
- arp -d Flushes the Address Resolution Protocol cache
- nbtstat –R Reloads the NetBIOS name cache
- ipconfig /flushdns Clears the DNS cache
- ipconfig /registerdns Registers the computer’s name on the appropriate DNS server
Collectively, this set of repairs takes care of most common network problems. If it doesn’t work, move on to more elaborate troubleshooting steps. A word of caution: The Repair button disables the current network connection first and then reenables and resets it. If you’re in the middle of a download or other important network activity, don’t try this!
Ed Bott 
A great tip since if you call your cable company, they run you through the gauntlet of useless, time-consuming steps more often than not. With this one, I could just say, “Done!”
I’m trying to hook up a new desktop for the first time to the internet. I can get an IP address, which means the connection is good. However, no websites will show up. When I try to repair the connection (which Windows tells me has “limited connectivity”), it fails at “Clearing DNS cache”.
ipconfig /flushdns only works when I disconnect the ethernet cable. With the cable on, it doesn’t matter what the status of the DNS Client service is (stopped, running, automatic, manual, etc).
Any clues? I really appreciate it.