1. Power on your PC computer and wait for it to boot up. Click on the 'Start Menu' icon at the bottom right corner of the screen. Input the phrase 'command' into the search field at the bottom of the screen. Right click on the result titled 'Command Prompt' and select the 'Run as Administrator' option. Wait as the command window opens.
2. Type in the phrase 'netsh int ip reset reset.txt' and press the 'Enter' key. Type in the phrase 'netsh winsock reset' onto the second command line and press 'Enter.' Type in the phrase 'netsh advfirewall reset' and press the 'Enter' key to reset the built-in Windows Vista firewall. Press the 'Exit' tab on the top right corner of the command window to exit. Click on the 'Start' menu icon and select 'Restart' to reboot your system.

3. Wait as your computer reboots. Launch your computer's Internet browser and try visiting your favorite website to ensure that your computer's Internet functionality has been restored.