I do not understand the question and therefor doubt if the one answer is going to be useful.
Is Linux installed on the 2nd drive?
If yes, did you install a bootloader? What did you do after the install--eg remove the drive? What else?
If Linux is not installed, then put the drive in the computer and boot from the install CD. It will give you the option of using either drive.
In any event, you do not need to "mount" one of the drives to install or use Linux along with XP.