shuttle sn45g

I am having trouble with my shuttle , it will only run for about an hour before it loses its internet connection ,the rest of the pc will still run ok, if I switch it off and on the connection will come back briefly before losing it again, when this first happened I turned up the speeds of the fans and this worked but now even with the fans on full time it still cuts off the internet, is the lack cooling causing this problem or is there another fault at the root of it , if not how can I cool the pc further. ---djemmo

this would be the wrong section for this...

LOL where did this come from