purchase the mobo from the same supplier? It sounds like he may have a bad batch. If the supplier tells you he has had no other complaints, take it with a pinch of salt. Fortunately, new legislation about to come into force makes the seller responsible for proving that an article sold had no problem when sold to you if you return it as faulty within six months of purchase. Doesn't help you this time I know. if you have no joywith the supplier, contact the maker with the serial number/batch number etc.