I'm at my wits end.

OK it wasn't a long journey to the end of my wits.

The problem: I can play TT in Quickplay and Solo play just fine. However, the trouble starts when I try to go on-line. I can see all the servers and when selected the player window shows who is on that server. When I join the server ,TT begins loading the map (I tried a stock map server) and then presto the Microsoft Send Error Message window (the exception is 0xC0000005).

I've Googled the error and it could be memory, video, full moon, etc.. My guess is the memory and video are just fine since I can play Solo and Quickplay within TT. That leaves network or OS issues.
Any help would be greatly appreciated. I really miss killing y'all!

Here are the details: I just installed a new mobo (aka motherboard ABIT AN52S) with a new Athalon 64 3500 CPU, 2 Gigs memory and a NVIDIA GEForce 7300 PCI-E 512MB DDR2. I sure miss my Win 98 lag machine.
I have installed, reinstalled and reinstalled WIN XP SP2 and all the latest updates. I have tried the onboard Gigabit LAN adapter and a different 10/100 PCI LAN adapter (with the onboard adapter disabled).
I also did a new download from Garage Games to make sure I had a clean TT install.