I have a system based on a 8KRAI Pro MB, with 2 HDs on the primary IDE, one set master (boot) the other slave.
I wanted to add a little more HD space, so I added a 160gb SATA connected to the SATA 1 connector, cloned the boot drive to it, rebooted to the BIOS and changed the HD boot order so the SATA goes first.
Upon reboot, I get the BOOT DISK error like there is no OS.
When I disconnect the IDE drives, the SATA boots OK.
If I go into the BIOS and set the 2 IDE drives to "none", the system boots OK, but does not show the drives when the BIOS posts.  Windows XP, however, shows the 2 drives and they seem to be functioning properly.
 
Does anyone understand why I have to effectively tell the BIOS that there are no IDE drives connected to the primary IDE channel in order to get the system to boot to the SATA drive, even though I have told the system to choose the SATA first?  Could this be a problem?  How the heck does XP know the 2 IDE drives are there?
 
Any help is greatly appreciated.  Thank you.