Onboard Adaptec 7895 - detects SCSI CD-ROM but not HDDs

[pgg]

This suggests this isn't a Knoppix-specific problem -

When I try to install Fedora Core 1 or 3 on the system, it can't find sda b c or d.

I put a Win XP Pro install CD in the system, and setup took a long, long time to produce

(Setup cannot access this disk.)
8386 MB Disk 0 at Id 0 on aic78xx

(Setup cannot access this disk.)
8386 MB Disk 0 at Id 1 on aic78xx

(Setup cannot access this disk.)
8386 MB Disk 0 at Id 2 on aic78xx

(Setup cannot access this disk.)
8386 MB Disk 0 at Id 0 on aic78xx

Any ideas why nothing can touch these disks? Thanks.