Can't access some websites with any browser

I'm running Windows 7 64-bit on a new Samsung laptop and accessing the internet okay via ethernet cable to my university's ISP. Some sites work fine (e.g. google.com) but I can't access others at all (microsoft.com, topshop.com).

I can't connect to those sites in safe mode with networking. And ping and tracert both fail. There's no proxy.

Other users can connect successfully to these sites using my cable and socket.

I've tried all the following with no success:

  • using various browsers (IE9, FF, Chrome)
  • creating a new user
  • updating drivers
  • clearing the DNS cache
  • using OpenDNS and Google's DNS
  • turning off Avast
  • tweaking the MTU
  • running MS malicious software removal tool
  • running Spybot S&D
  • reviewing the hosts file
  • disabling the IPv6 options
  • repairing / resetting winsock settings
  • disabling advanced javascript options

I have run out of ideas... can anyone see anything I've missed??!


I had a similar issue and it was because of MTU size but I see you have already tried that idea. Also I was on DSL and was using PPPoE.

Try setting your Laptop MTU to be much lower say 1000 and see if it works. Then adjust your MTU to be higher.


If pinging www.google.com on the affected computer resolves the same as it does on a working computer then the issue is not related to DNS lookup. If you have tried two DNS providers like OpenDNS and Google I doubt this is the issue.

If is doesn't resolve to an IP address or resolves to a local ip address like 127.0.0.1 then you have a DNS problem or are infected. Not being able to resolve www.microsoft.com is a classic virus tactic to stop you getting updates or support.

If you can't ping the resolving IP address either that address does not respond to pings for security reasons (www.google.com does though) or something is blocking you. Turn of Windows Firewall and any other port blocking firewall software.

Finally, check you only have one network connection active and your computer is using the right one. Turn off Wireless and Bluetooth for example.