If all your keg beers and lagers are serving warm you have a major problem.
If you have a large pub or hotel then you will probably have one or two remote coolers. These will often be located somewhere near your cellar. They are, a large box like machine with lots of pipes coming from the top.
Once you have located the machine make sure it is switched on. This is the only thing you can check. Even if the machine is running it may still be faulty.
Ring your local Tech Services right away