I had issues with Guild wars2 seemingly killing my internet connection. The game would loose connection , as well as my internet going offline. My internet would then come back on after a few seconds. This would happen several times a day, but not effect any other pc running GW2 on the same network.
So I tried assigning my pc a dedicated IP of 192.168.0.9 , which is outside the DHCP pool on my router.
Not had one crash or disconnect in over a week. Time will tell if this was a true fix.