AVI & WMV Cause computer to lock up.

[66lemieuxjagr68]

Does anyone know why when I run Mpeg videos on my dell 8100 1.4, p4, system, they run fine, but avi and wmz 90% time causes my computer to lock up and I need to reboot? Once I reboot, they work for like 10 minutes, then after that, they continue to lock me up, I do not get it at all, tried everything, running plenty of memory too, so what gives?

Thanks
Gary