Can't connect to the Internet anymore

I have a Windows 7 computer that could connect to the Internet fine before. Now suddenly I can't get online with it. I have to use my old XP computer to get online. So it's obviously not a problem with my ISP since the XP computer still works. What can I do?

Always start troubleshooting at the hardware level. Make sure your network cable is connected (and try swapping it out for a different Ethernet cable) or if you're using wi-fi, make sure wireless is turned on. Many times I've seen people forget to reenable wi-fi after disabling it on a plane and then think there was something wrong with the computer.

If all that checks out, run the built in network troubleshooter in Windows 7. This article tells you how:

If that doesn't work, try booting the computer in safe mode with networking, and/or try booting without loading third party applications (clean boot mode). You can find out more about that here: