Yesterday I updated Windows Vista Home Premium. My internet was not working after the update. I solve the problem of having no internet by uninstalling my firewall software, and using Windows builtin software Firewall. Now I have my internet back.
Other solutions to getting your internet back after a Windows Update can include uninstalling your network card driver and reinstalling. See if DHCP service is running in Windows by going to Start > Run >type services.msc.
If none of those solutions work, you can do a system restore to before you installed the updates for Windows.
This can also happen if you upgrade your firewall software. All you have to do usually is uninstall your fire wall software, and reinstall it, find another firewall program, or use the one built into Windows XP, Vista, or 7.
Note: It is besst to stay calm, and think logically, and answer these questions: What has changed?, Is it possible for the changes to cause the problem, When did the problem start to happen?, and What are some possible ways to fix the problem? It also help to break the problem down into smaller individual problems.