external hdd


i bought a external hdd it worked fine while my pc was vissta then i installed xp and took vista off and the external hdd wont work on any xp computer and i need whats on urgently so i dont wanna reformat it.
it says its there but it wont read the files or let be coppy them
can some one help please??
ive thrown away the box but kept everything in but i cant remember the moddle of it all i know is its half a terrabite hdd and its made by seagate.
Right click on "my computer" -> Manage -> Disk Management.

Assign the drive a letter with "Change drive letters and paths" by right-clicking on the partition there. You should than be able to access the device as a drive in "my computer" under the letter assignment you gave it.