Hello There,
A friend has asked me if I can retrieve files off here hard drive. Can I do this by connecting the hard drive to the IDE slave cable and hooking up the power plug to it? Also I would like to know if my OS system will activate the 2nd hard drive or do I have to use a reboot disk?
Thank you

Yes, you can connect it as a slave. First make sure the CMOS setup recognizes the drive, then you will need to assign a drive letter to it in the OS (if that isn't done automatically).