I have a pre-built computer with a gigabyte ga-78lmt-usb3 motherboard. After installing Windows XP, the USB 2.0 ports work fine, but I can't get the 3.0 ports to work as 2.0 ports. I've tried to uninstall and reinstall drivers, disable the USB ports, turn OFF USB 3.0 in the bios--but nothing is working. I still have a yellow question mark in the device manager. I found some info online that said to have the xHCI Mode set to Auto or Smart Auto in the BIOS, but there is no xHCI mode anywhere in my BIOS from what I can see. Any suggestions would be greatly appreciated. Thanks.