Unusual FPS drops

About a year ago I played guild wars, on the same exact machine im running now with about a constant fps of 30-50 with almost no problems at all. Now I have returned to guild wars, but for some reason my fps can sometimes drop to even 6 or 7! If I stand still I get an fps of about 20-30 but if I start moving my fps drops crazy low. I don't see how this is happening because before when I played I got double the fps with no fps drop when I was moving. My connection is good, 100-200ms so that's why I didn't post in the connection lag thread, sorry if this isn't supposed to be here though... feel free to move it.

But anyways I also have way over the recommended system requirements, as you can see.
-AMD Sempron 3000+ 2.0ghz
-2gb of ram
-ATI Radeon HD 2400 pro 512mb (Latest Omega Drivers)
-120gb hard drive

I've defragged guild wars and the entire computer with the program from the thread, checked for malware, dumped dns cache, and most things you could think of.

Edit: Thought I'd read carefully enough. Looks like he has most recent Drivers...

Possibly clearing the dust out of every corner of your computer would work. Also, set your graphics to low if you don't really mind it being a bit lower quality, but will allow for better gameplay.

⌐Snow⌐