Hello dear superuser community.

I had no idea where to post this because it is a problem that completely baffles me. I have a lot of experience with network configuration, but I am completely out of ideas on how to fix this.

I have a Fritz!Box branded router on my ISP 1&1 in Germany. My computer is connected to it with a normal Ethernet cable. I always manually set my IP on the computer and use the Google DNS servers for name resolution. I also tried OpenDNS and the result is the same. With that configuration the following happens:

• Google search responds with big delay
• Gmail, Google Calendar & Google Drive requests time out the majority of the time

In order to troubleshoot, I set the network connection to DHCP for both IP & DNS. At that point, what happens is the following:

• Google search times out most of the time
• Gmail, Google Calendar & Google Drive work most of the time

Sometimes, it happens that the sites that time out will come up, but weirdly enough, the pictures on the buttons will be missing. For instance, the magnifying glass on Google will be gone or the circle arrow on Gmail (but all buttons of course).

All other websites load just fine - and very quickly. All other network functionality is completely unimpacted. The behaviour of fixed IP & Google DNS vs automatic IP & DNS is easily reproducible.

I am going crazy trying to fix this as I have no idea what the hell is going on at this point. Here a list of the things I have tried thus far:

• Flushed the DNS
• Tried on different browsers
• (Works fine on my laptop by the way)
• Tried disabling Teredo & IPv6 stack
• Emptied all caches
• Checked the HOSTS file
• Rebooted the router
• Reset the router
• Reinstalled the network adapter
• Tracert displayes normal route until timing out at one point
• Ping usually doesn't work for the unreachable sites either
• Ran both complete Norton 360 & Kaspersky 2012 scan
• Ran Kaspersky Virus Removal Tool in safe mode
• Tried connection in safe mode & networking enabled

If you have any ideas, please let me know. I'm getting desperate...