One beep, system powers up, then shuts down

Is well known that elitegroup motherboard have this problem, try it to dissasemble another time yor matherboard, let it out of case reasemble pieces out of case switch on and look if the system is stabile or not, if it is, prior to put *********** board to the case put under the mainboard aplastic film then mount in the case, this must solving your problem, if even out of case the system is reseting disconect any devices and let ontly floppy drive on it with ram and processor too , download from internet newer version of your bios and make it a new flash from floppy drive, this mut resolve your problem definitely to you. in any case dont forgt to put plastic film under mainboard(withaout scotching them or sometthing like this) and mount it in his place.