Had installed a new WDH

Question

Had installed a new WDH ICS 5000A into the USB port of my 512 G of RAM computor running Windows XP. I have all of my document files etc. downloaded onto it (about 35GB) I replaced Windows with a newer edition (Still XP) which is working on all functions other than this unit, which no longer appears to be recognised by my computer.How can I get it to work and allow me to access my saved documents etc?