first off, check all your cables. is this a fresh install, or upgrade to sp1 where they worked fine earlier? if all your cables work fine, make sure you have all the right drivers for your motherboard, and any special chipset drivers you might be lacking. are your drives on a controller card, as i see some scsi there. you may need to fully remove your drivers and reinstall as well. i would say just check the obvious. also, need more info on the setup / situation
not a fresh install - system has been running flawlessly for the past year. checked cables, they are fine. nothing has changed - just all of a sudden, i try to get some data from a disc, open up my computer and no optical drives. they are off the mobo - no controller card, that's virtual drives from daemon tools