here's what I would do.
put it on the regular IDE channel, make sure Windows is cool, etc. & you have the drivers for the promise installed.
when it asks you to restart, say no & shut down manually instead
move the cable to the ata100
when you boot again, enter the bios & do the following
[*]there should be a setting
detect promise controller make sure it's auto, or enabled.
[*]move to the "1st" boot device, & change it to ata100 ( i think it says ata100, might say SCSI, can't remember right now -
consider my nick 
)
i think that should do it, I can check when I get home.
gl
joinT