Can video card freeze system…

Can an AGP video card (VooDoo 3500 with 16megs of on card RAM) be the culprit of my system freezing (especially when running video or a significant screen change (like menus opening)? I have had this problem for a while and when it occurs, the system responds to nothing but hitting the power switch off. I swapped out the 256 RAM stick with new Kingston (instead of the generic I was running). I also recently upgraded to XP. Yet still have this problem. I am running an Athlon 750 on an EPOX 7-KXA board. Any suggestions or similar experiences greatly appreciated.