Weird networking problem ( Linksys, Windows 7 )

Okay it's a bit tough to figure out where to start from, but here is the basic summary of the issue:

During general internet usage, there are times when any attempt to visit a website stalls at "Waiting for somedomain.com". This problem occurs in Firefox, IE and Chrome. No website will load, INCLUDING the router configuration page at 192.168.1.1. Curiously, ping works fine, and other network apps such as MSN Messenger continue to work and I can send and receive messages. Disconnecting and reconnecting to the wireless network seems to fix the problem for a bit, but there are times when it relapses into not loading after every 2-3 http requests. Restarting the router seems to fix the issue, but it can crop up hours or days later.

I have a CCNA cert and I know my way around the Windows family of operating systems, so I'm going to list all the things I've tried here.

• Other computers on the network seem to suffer the same problem, which makes me think it might be a specific problem with something in Win7. The random nature of this issue makes it a bit difficult to confirm, but I can definitely say that I have experienced this on the following systems:
  • Windows 7 64-bit on my desktop
  • Windows Vista 32-bit on my desktop ( the desktop has 2 wireless NICs and the problem existed on both )
  • Windows Vista 32-bit on my laptop ( both with wireless and wired )
  • Windows XP SP3 on another laptop ( both wireless and wired )
• Using Wireshark to sniff packets seemed to indicate that although HTTP requests were being SENT out, no packets were coming in to respond to the HTTP request. However, other network apps continued to work i.e I would still receive IMs on Windows Live Messenger.
• Disabling IPV6 had no effect. Updating router firmware to the latest stock firmware by Linksys had no effect. Switching to dd-wrt firmware had no effect. By "no effect" I mean that although the restart required by firmware updates fixed the problem at the time, it still came back.
• A couple of weeks back, after a LOT of googling and flipping of various options, I figured it might be a case of router slowdown ( http://www.dd-wrt.com/wiki/index.php/Router_Slowdown ) caused by the fact that I occasionally run a torrent client. I tried changing the configuration as suggested in that router slowdown link, and restarted the router. However I have not run the torrent client for 12 days now, and yet I still randomly experience this problem.

Currently the computer I am using is running Windows 7 64-bit. I would just like to reiterate some of the reasons that I was confused by the issue.

• Even the router config page at 192.168.1.1 would not load, indicating that it's not a problem with the WAN link, but probably a router issue or a local computer issue. For some reason, disconnecting and reconnecting to the wireless network immediately seems to fix the problem.
• Updating the router firmware, even switching to open source firmware did nothing. So it seemed to be a computer issue.
• On the other hand, I have not seen any mass outrage of people having networking problems with Windows 7 and Linksys routers, especially a problem of this sort, and I have tweaked every network setting I could think of.
• Although HTTP seems to have trouble, ping works fine, DNS lookups work fine, other networking apps work fine. However if I disconnect from Windows Live Messenger and try to reconnect, it fails to reconnect. So although it could receive data over the existing TCP/IP connection, trying to start a new one failed?

Does anyone have any further ideas on debugging or fixing this issue? I am reasonably certain there are no viruses or other malicious apps on my network, and I am also reasonably certain that nobody is accessing my router without my consent.

Router: Linksys WRT54G2 1.0 running dd-wrt firmware
Wireless Card: Alfa AWUS036H
OS: Windows 7 64-bit

EDIT: I tried switching to a clean wireless channel free from interference, but the problem still persisted. I tried connecting directly with a cable, but the problem still persisted.

Solution 1:

Have you tried using ethernet directly to see if it still happens? If it does we can rule out anything to do with wireless directly. Try watching your signal strength when the issue occurs, it could be interference. I have a friend who's wireless signal would cut drastically, allow existing connections to work, and prevent any new connections from being made when he or his wife opened their garage. Changing the channel the router was using fixed the issue. (Their garage frequency was on the equivalent of channels 6 and 7 on 802.11b/g)