Booting problem with external disk (USB)

Hi all. I'm instaled SuSE 9.3 in a external disk (usb) in my laptop. I 've an hda (DVD/CD), HDC (Internal disk whith 2 windows partition hdc1/hdc2) and an external disk (usb)  which was reconigzied as SDA. In the previous mentioned booting order. SuSE did by default: sda1 - FAT sda2 - SWAP sda3 - ext3 When the system reboots after instalation it does'nt find any partition. I try the safe mode with not result . any idea ? best regards Raúl H. Lapitzondo