Restarting PC (but different this time)

[Shibathedog]

My PC is always on, i never turn it off, and every couple days (Probably like once a week) It will restart itself (like a hard shutdown type deal) I suspect its the chipset overheating, is this even a possibility? There is a heatsync on the north bridge but nothing on the south bridge. Buying a chipset fan isnt really that big of a deal ill do it. Or could it be something else?

 

All my temps are really low so i dont think its the CPU/etc. My mobo doesnt give me a temp on the chipset so i guess thats why i think its that.

 

Its also not overclocked right now.