When I browse with Firefox I will randomly get disconnected from the internet for roughly a minute then connection re-establishes itself. When this happens I can't ping any outside network. I originally thought it was an ISP or network issue, but I have tested the connection by going to the same website from another PC on the network, while I am unable to connect on this PC. I also tested this PC for connectivity issues without Firefox running and found no problems. I have spent hours browsing with 3 other browsers and had no connectivity issues. I tested this downloading a large torrent with 4 global connections at low speed to confirm connectivity. During tests with the other 3 browsers I haven't had an issue. Within minutes of opening Firefox I lose connection, check the torrent, it will be losing bandwidth, and pings to any outside network time out. One thing I have noticed is if the browser is not changing pages this issue doesn't occur, it seems to only happen while browsing, which leads me to believe it has something to do with connecting to websites or DNS lookups. I used to have Firefox 3.6 and had this issue, the upgraded to Firefox 4.0. The issue is still there but with Firefox 4.0 it is far less frequent, yet still happens. I have already narrowed it down to Firefox. I don't have any firewall running on this PC, only the router firewall, which I had disabled during tests. I upgraded Firefox from 3.6 to 4.0, clean installed Firefox 4.0 twice and no change in the problem, except the frequency of the problem which is far less in Firefox 4.0, but still there. I have read it may be an issue with IPv6 but I have disabled it in Firefox and in windows itself. My system specs are: Intel Core i7 930 12GB G.SKill PC3 12800 @ 1600MHz Asus Radeon 5870 Intel 16GB SSD (OS and Firefox installed) Seagate 1TB HDD (storage drive) Intel DX58SO All running at stock. Any reasonable suggestions would be welcome. Please contact me if you require any additional information.