Boot issue with XP installed twice on seperate partitions

[Guest]

I have a friend's computer that has had XP installed twice - once to each
partition of an existing SATA hard drive. He had XP installed on the first
partition (which was labeled C, then installed it again to the second
partition. This second partition somehow then saw itself as the first
partition and labels itself C: now. Both boot.ini files on either partition
are set to boot from the first partition. The computer was running fine for
a while with the second partition somehow being the one to boot and label
itself as the first partition and the C: drive. I plugged in a bad IDE hard
drive from another computer just to access the data thereon. Everything was
still booting "normally" at that point (from the newer XP install.) However,
now if I remove the IDE hard drive, the computer will revert back to booting
from the older XP install. Plugging the IDE drive back in will switch it to
booting from the newer XP install. Again, both XP installs on either
partition have a boot.ini that refers to the first partition. My questions
are why is this happening, and what can I do to correct it - to get it to
boot from the newer XP with the IDE drive removed. I have tried modifying
the boot.ini to boot from the second partition, but it will not boot at all
like that.

 

[John John]

Using the Windows XP built in Disk Management tool verify the active
status of the partitions, flag the one that you want to use as active.
You can use a Windows 9x startup disk and fdisk or a third party
partition manager (like BootItNG) to toggle the active partitions.

John