Brand new install of 10.3 with all updates on B&W G3 with a 2940U2W adaptec card and SCSI drive. All working great. -shut down and added an NEC based USB 2.0 controller. Rebooted. All is good. USB card is working too. Nice! -shut down and put in a Sonnet ATA133 controller and an unformatted WD 200gig IDE (to be a second disc for storage). Booted and all seemed well. Created a single partition and formatted 200g drive (186 actually) and drive mounted fine on desktop. -rebooted and got the do not enter sign after a minute or so of sitting on the grey screen. Pulled out the ATA controller and IDE drive. No boot still. Pulled out the USB 2.0 controller. No boot. Zapped the PRAM just incase and still no go. WTF ! I have not even put in one piece of additional software. Its all apple detected hardware and updates in there. I even reconnected the SCSI cable and reseated the card. No go. Took the drive over to my PC and it comes up in the adaptec bios. I can go in windows management and format the drive if I want so I know the drive is ok because its visible and appearantly working fine. Can OSX be confused after detecting the ATA controller about what its supposed to boot from?