Chances are it hasn't flashed properly. I'm not sure of what else you can do other than attempting to RMA it if that's possible. If it has a removeable BIOS chip then you might be able to send it back to Gigabyte to get it re-flashed so you can use the board again. For future reference though, never EVER flash a BIOS from Windows, always use DOS with (preferably) a USB key. Floppy disks are fine, but there's a higher chance of it not reading the data properly as floppies aren't ultra reliable.