The 4.43 VIA drivers were problematic even on my KT266A system. Have you tried running XP without installing any VIA drivers at all? The ones that come with XP are really good, especially on older chipsets - they were awesome on my old KT133A board.
Other than that, I don't know what to tell 'ya. Perhaps go back to an older set of detonators like the 30.82's or 29.42's if you haven't already. Or, try the latest leaked 40.52's or wait until tomorrow when NVIDIA is supposedly going to release new official drivers.