What HS can I use for Epox 8KTA2 ... sometime restart itself ??

[dvdman3]

Using Win2k, SP2 + every other fixes DX8... etc, 512 MB. I am not sure when doing something like Divxing or Converting mp3... and surfing the net at the same time... like now.. the computer will just restart by itself. Is it a sign of heat related issues or stress to the computer ? What HS fan can I use for the Epox 8KTA2 ?? Thanks