This happened to me about 4 months ago. I called Time Warner, they had me run a traceroute and all, told me that it was my computer, my modem was working fine.

The next day, it started working again.

Now over the weekend, its happening again.

I am connected at 12 MBps, but my browsers won't let me online. I can't figure it out.

I have Road Runner with a wireless modem/router, but the router is connected to my PC via usb.

My system specs:
Proc : AMD Athlon 64 Processor 3000+* (1.8GHz) 939pin
Mobo : EVGA 133-K8-NF41 NF4SLI 939
Video : One VGA EVGA GeForce 7600GT 256-P2-N553-AX
Ram : 2 GB (512X4) Corsair DDR400
DVD burner: Pioneer DVDRW DVR-111D 16x8x8x6 IDE ATAPI 2MB 130ms Dual Layer Black
Hard drive : Seagate Barracuda 160GB 7200 RPM
Case & PS : Antec Sonata2 ATX QUIET Mid 450W
Sound Card : CREATIVE|AUDIGY 2
CPU Cooling : Thermaltake Copper XP-90C with EXTREMELY LOUD 92mm Tornado fan
Monitor: Westinghouse 37” 1080p LCD LVM 37W3

To clarify, I am running Windows XP home and trying with the latest versions of firefox as well as internet explorer.

just to add to your dilemma, I too was suffering this problem, to overcome this I removed all wireless networking including the router and everything was fine but I share the connection from the main source so I have to suffer the wireless problem of routing. I have to keep clearing my connection to the network, reboot and away I go again, sometimes for hours and even days. Some serious issues have cropped up lately with routers and browsers in the last year as we have discovered at Brunel University in London. The internet and protocols are changing and more and more people are suffering this problem world-wide. PS. We also refuse to use explorer 7 as it is so full of bugs its not worth the problems it causes. Microsoft again rolling out something and letting the world report its faults. All the Macs we use are full steam ahead and never go down, and i'm not a great lover of mac's

Not sure if the issues are the same, as my modem is both a normal modem as well as a wireless router, but my PC is connected via USB cable, not wirelessly.

Thanks for the reply.