BOOT FAILS: sy-p4rc350 and Adaptec SCSI (only one disk)

Hi.
I have sy-p4rc350 and I was able to boot NT 2k installation from CD (CD
is on second IDE - slave, 1st IDE is disabled) and finish it
successfully, but after rebooting the PC I got "Reboot and select
proper Boot Device or Insert Boot Media in selected Boot device and
press a key."
P4 3.2 GHz 800
Both IDE DISABLEd now.
SCSI disk - st15150w Seagate Barracuda 4 GB SCSI2
Adaptec 7800 SCSI3

Disc is recognized by SCSI bios (Adaptec) and is at 0.

BIOS boot sequence: [SCSI Card] only. All other devices removed.
I suspected SCSI Card starts probing from highest speed (scsi wide/not,
sync/async, etc) and I played with Adaptec settings for target 0 (where
disk is) - not helped. Adaptec is at 7. No other devices on Scsi bus.

Anybody else experienced similar problem?

Thanks for your help!