Overheated network cabinet

My friend was working on creating his own small server room in his house. Well it was nothing special or big but still it was something new in our neighborhood. I decided to help him due to the fact that I had some basic knowledge about computers and server systems. Together we prepared a small room on the first floor of his house and then we created a small computer centre that he called a server room or a control room. He installed there a big amount of different computer equipment, hard drives, hubs and routers. He even plugged in his computer to three surveillance cameras that he installed in his house and in the garden. He put all this stuff into a thing called a network cabinet and everything is safe there and in one place. Everything was working perfectly but only for a few hours. Then something went wrong and his computer started to restart from time to time. He checked all the wires and equipment but he did not find anything suspicious. On the next day when nothing has changed he decided to call for professional help. The guy who visited him and checked the equipment told him that the network cabinet was overheated. It seems that it was the producer"s fault and only two of the four fans were working to cool the network cabinet. Due to high temperature the computer was restarting. He repaired it and now everything is working just fine. And I have learnt how important the cooling system in the network cabinet is.