He should definitely try these suggestions in this order until something works:
- Update his browser to the latest version.
- Run a full virus scan and spyware scan
- Additionally, if he uses ZoneAlarm or a similar firewall, try disabling it temporarily and see if that helps.
- Check C:\Windows\system32\etc\drivers\hosts to make sure there are no erroneous entries there (beyond the typical 127.0.0.1 entry)