Occasional 45 sec freezes while playing FFXIFollow

OS: Win2000
Processor: AMD Athlon 64 3200+, ~2.2GHz
Memory: 1022MB RAM
HD Space: 135/230GB free
Page File: 490MB used, 1685MB available
Video: NVIDIA GeForce 7800 GS (Just updated the drivers this week)
Motherboard: Asus K8V SE Deluxe
Use Archbell Windower 3.23 (No moralizing please)

Problem:
About once a day, but sometimes a few times a day, my computer will just mostly lock up while playing FFXI. I've noticed it mostly in crowded zones, but that may be because I spend most of my time in crowded zones. What happens is my screen will freeze. Looking at my router, it will stop registering any network traffic to this computer. I can use my mouse outside of FFXI and attempt to open programs and such, but even the mouse cursor moves sluggishly and programs will not really finish loading until the spell passes. Eg, I'll open up Firefox and after about 5 seconds a window will pop up, but it won't load my homepage for a solid 45 seconds until the little freeze has passed. 90% of the time, by the time it has passed, the server will have booted me off of FFXI.

This could be a general hardware, OS, or driver issue, but it has only happened while playing FFXI. While I may not play other programs as often as FFXI, some of the ones I do play (Oblivion) are far more demanding. Windower could be the culprit, but this problem has persisted with various versions of the Archbell Windower and I'm fairly certain it has happened before without using a windower. I suspected it was my video card overheating, but I have checked with the temperature monitor and it has never gotten close to the "danger zone." I run the computer with the side panel off to help cooling and dust occasionally. My best uneducated guess is that it's an issue with my RAM, but maybe someone can give me an educated guess.