have you tried front and back USB ports?
if all USB-ports fails the controller might not work correctly...
if the BIOS has crashed:
floppy still works?
then download a bootable BIOS flash version from fujitsu supporthttp://support.ts.fujitsu.com/Index.asp?LNG=en
windows still works?
then download the newest BIOS BUP-file for your D2312-A1/2/3-board from fujitsu support
and flash the BIOS with dskflash
if all this doesnt work:
search for Flash Memory Recovery
special jumper settings needed (depending on board)
>Recovery BIOS and BIOS Update