error with drive after reinstall of windows xp pro

hi i am having a little probloem with my drives my primary is running great but my secondary isnt showing up in my computer i have checked the bios its fine there and i have checked in disk management in windows and it is there it shows the partition in my secondary and says it is active and healthy i have tried assigning a letter but it will not allow my to do anything but format but that will be my last resort as this drive was my back up 🙁 so any info about this will be much apreciated thank you