I have four DVD's in my main computer,two BR's and two SD. The fouth drive is a DVD-ROM,it worked for about a year then suddenly dis-appeared in Windows XP. I changed the motherboard SATA connector and it briefly re-appeared,then again dis-appeared. I've changed to a different DVD-ROM,changed the motherboard SATA connector and the power connector several times but I can't get Windows to recognize it. The DOS boot screen shows four DVD's but the fourth one keeps dis-appearing when Windows XP loads.