Make drive non-bootable.

OK, this is a weird request so here it goes.

I had a RAID1-01 set of boot-able 500g drives plus another 500g drive for backup.
One of the drives failed so I bought 2 each 1tb drives. Replaced the failed drive and let the RAID1 rebuild. I then decided to replace the good 500g drive with the other 1tb drive. This was accomplished easy enough, so now I have a 500g from the mirrored system pair and the backup 500g drive.
So now i create another mirrored pair of the 500g drives RAID1-02. This went fine, too.
Now for the problem. sometimes when the system reboots, the RAID1-01 drives must not be available and the system tries to boot from the 500g raid set and will just sit on the black screen with the cursor blinking in the top left corner. If i power down and F12 coming up the boot list shows up and i select RAID1-01 with 1tb drives and the system boots normal.
I think the issue is that the system still sees the RAID1-02 as bootable even though i have disable this in CMOS.
Any ideas? or how can i make the second raid set unbootable?

Adrian said:

Investigate the boot priority in the BIOS.

The boot priority is set to RAID1-01 and CD/DVD, nothing else.

A Description of the Diskpart Command-Line Utility

Set the errant RAID partition to inactive and see if the problem goes away. Report back.

speedy1971 said:

A Description of the Diskpart Command-Line Utility

Set the errant RAID partition to inactive and see if the problem goes away. Report back.

I don't see an inactive command in DISKPART only the active command.