What makes you sure it isn't?
Why does it run fine on most machines?
We are not
sure However not all of us are are computer illiterate, some of us have done a complete fresh setup of XP with only basic stuff installed, and up to date drivers. I went through ever ypossible AH configuration, even with lowest settings. And still no luck, while all other applications (video editing, varous graphic-heavy games and so on) run fine. Personally I suspect there may be something up with AH, textures and the dual core, but that's only speculation
And "running fine on most machines" doesn't mean much at all, especially when there is more with one or two players still having trouble,and most of them with a similar hardware configuration
But I will be glad to hear your advice how to fix it. I'm currently running out of ideas.